Tagged: MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 10:11 pm on December 30, 2021 Permalink | Reply
    Tags: "Three rings to bind them all-The inner planets- Cosmic history can explain the properties of Mercury; Venus; Earth and Mars", , , , How to build an asteroid belt, MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), Outer planets and Kuiper belt, The first image taken by the ALMA observation after its completion in 2014., The formation of planetesimals – the small objects between 10 and 100 kilometers in diameter that are believed to be the building blocks for planets., The results suggest a direct link between the appearance of our solar system and the ring structure of its protoplanetary disk., The young star HL Tauri, There are pressure bumps associated with particularly important transitions in the disk that can be linked directly to fundamental physics [described in the post].   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) : “Three rings to bind them all-The inner planets- Cosmic history can explain the properties of Mercury; Venus; Earth and Mars” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    December 30, 2021

    Dr. Markus Pössel
    Head of press and public relations
    MPG Institute for Astronomy, Heidelberg
    +49 6221 528-261
    pr@mpia.de
    Bertram Bitsch
    MPG Institute for Astronomy, Heidelberg
    +49 6221 528-427
    bitsch@mpia.de

    Astronomers have managed to link the properties of the inner planets of our solar system with our cosmic history: with the emergence of ring structures in the swirling disk of gas and dust in which these planets were formed. The rings are associated with basic physical properties such as the transition from an outer region where ice can form where water can only exist as water vapor. The astronomers made use of a spread of simulation to explore different possbilities of inner planet evolution. Our solar system’s inner regions are a rare, but possible outcome of that evolution. The results have been published in Nature Astronomy.

    1
    This image, taken with the ALMA Observatory in 2014, was the first to reveal a ring-like structure in a protoplanetary disk – in this case, the disk around the young star HL Tauri.

    The visible disk has a radius of a bit over 100 astronomical units, that is, over 100 times the average Earth-Sun distance. For comparison: In our solar system, the maximal distance of Pluto from the Sun amounts to about 50 astronomical units. The research described here shows the key role ring-like structures like this are likely to have played in the genesis of our Solar System.

    © ALMA (ESO/NAOJ/NRAO)

    The broad-stroke picture of planet formation around stars has been unchanged for decades. But many of the specifics are still unexplained – and the search for explanations an important part of current research. Now, a group of astronomers led by Rice University(US)’s Andre Izidoro, which includes Bertram Bitsch from the Max Planck Institute for Astronomy, has found an explanation for why the inner planets in our solar system have the properties we observe.

    A swirling disk and rings that change everything

    The broad-stroke picture in question is as follows: Around a young star, a “protoplanetary disk” of gas and dust forms, and inside that disk grow ever-larger small bodies, eventually reaching diameters of thousands of kilometers, that is: becoming planets. But in recent years, thanks to modern observational methods, the modern picture of planet formation has been refined and changed in very specific directions.

    The most striking change was triggered by a literal picture: The first image taken by the ALMA observation after its completion in 2014. The image showed the protoplanetary disk around the young star HL Tauri in unprecedented detail, and the most stunning details amounted to a nested structure of clearly visible rings and gaps in that disk.

    As the researchers involved in simulating protoplanetary disk structures took in these new observations, it became clear that such rings and gaps are commonly associated with “pressure bumps”, where the local pressure is somewhat lower than in the surrounding regions. Those localized changes are typically associated with changes in disk composition, mostly in the size of dust grains.

    Three key transitions that produce three rings

    In particular, there are pressure bumps associated with particularly important transitions in the disk that can be linked directly to fundamental physics. Very close to the star, at temperatures higher than 1400 Kelvin, silicate compounds (think “sand grains”) are gaseous – it is simply too hot for them to exist in any other state. Of course, that means that planets cannot form in such a hot region. Below that temperature, silicate compounds “sublimate”, that is, any silicate gases directly transition to a solid state. This pressure bump defines an overall inner border for planet formation.

    Farther out, at 170 Kelvin (–100 degrees Celsius), there is a transition between water vapour on the one hand and water ice on the other hand, known as the water snowline. (The reason that temperature is so much lower than the standard 0 degrees Celsius where water freezes on Earth is the much lower pressure, compared to Earth’s atmosphere.) At even lower temperatures, 30 Kelvin (–240 degrees Celsius), is the CO snowline; below that temperature, carbon monoxide forms a solid ice.

    Pressure bumps as pebble traps

    What does this mean for the formation of planetary systems? Numerous earlier simulations had already shown how such pressure bumps facilitate the formation of planetesimals – the small objects, between 10 and 100 kilometers in diameter, that are believed to be the building blocks for planets. After all, the formation process starts much, much smaller, namely with dust grains. Those dust grains tend to collect in the low-pressure region of a pressure bump, as grains of a certain size drift inwards (that is, towards the star) until they are stopped by the higher pressure at the inner boundary of the bump.

    As the grain concentration at the pressure bump increases, and in particular the ratio of solid material (which tends to aggregate) to gas (which tends to push grains apart) increases, it becomes easier for those grains to form pebbles, and for those pebbles to aggregate into larger objects. Pebbles are what astronomers call solid aggregates with sizes between a few millimeters and a few centimeters.

    The role of pressure bumps for the (inner) solar system

    But what had still be an open question was the role of those sub-structures in the overall shape of planetary systems, like our own Solar system, with its characteristic distribution of rocky, terrestrial inner planets and outer gaseous planets. This is the question that Andre Izidoro (Rice University), Bertram Bitsch of the Max Planck Institute for Astronomy and their colleagues took on. In their search for answers, they combined several simulations covering different aspects and different phases of planet formation.

    Specifically, the astronomers constructed a model of a gas disk, with three pressure bumps at the silicates-become-gaseous boundary and the water and CO snow lines. They then simulated the way that dust grains grow and fragment in the gas disk, the formation of planetesimals, the growth from planetesimals to planetary embryos (from 100 km in diameter to 2000 km) near the location of our Earth (“1 astronomical unit” distance from the Sun), the growth of planetary embryos to planets for the terrestrial planets, and the accumulation of planetesimals in a newly-formed asteroid belt.

    In our own solar system, the asteroid belt between the orbits of Mars and Jupiter is home to hundreds of smaller bodies, which are believed to be remnants or collision fragments of planetesimals in that region that never grew to form planetary embryos, let alone planets.

    Variations on a planetary theme

    An interesting question for simulations is this: If the initial setup were just a little bit different, would the end result still be somewhat similar? Understanding these kinds of variations is important for understanding which of the ingredients are the key to the outcome of the simulation. That is why Bitsch and his colleagues analyzed a number of different scenarios with varying properties for the composition and for the temperature profile of the disk. In some of the simulations, they only the silicate and water ice pressure bumps, in others all three.

    The results suggest a direct link between the appearance of our solar system and the ring structure of its protoplanetary disk. Bertram Bitsch of the Max Planck Institute for Astronomy, who was involved both in planning this research programme and in developing some of the methods that were used, says: “For me, it was a complete surprise how well our models were able to capture the development of a planetary system like our own – right down to the slightly different masses and chemical compositions of Venus, Earth and Mars.”

    As expected, in those models, planetesimals in those simulations formed naturally near the pressure bumps, as a “cosmic traffic jam” for pebbles drifting inwards, which would then be stopped by the higher pressure at the inner boundary of the pressure bump.

    Recipe for our (inner) solar system

    For the inner parts of the simulated systems, the researchers identified the right conditions for the formation of something like our own solar system: If the region right outside the innermost (silicate) pressure bump contains around 2.5 Earth masses’ worth of planetesimals, these grow to form roughly Mars-sized bodies – consistent with the inner planets within the solar system.

    A more massive disk, or else a higher efficiency of forming planetesimals, would instead lead to the formation of “Super-Earths,” that is, considerably more massive rocky planets. Those Super-Earths would be in close orbit around the host star, right up against that innermost pressure bump boundary. The existence of that boundary can also explain why there is no planet closer to the Sun than Mercury – the necessary material would simply have evaporated that close to the star.

    The simulations even go so far as to explain the slightly different chemical compositions of Mars on the one hand, Earth and Venus on the other: In the models, Earth and Venus indeed collect most of the material that will form their bulk from regions closer to the Sun than the Earth’s current orbit (one astronomical unit). The Mars-analogues in the simulations, in contrast, were built mostly from material from regions a bit farther away from the Sun.

    How to build an asteroid belt

    Beyond the orbit of Mars, the simulations yielded a region that started out as sparsely populated with or, in some cases, even completely empty of planetesimals – the precursor of the present-day asteroid belt of our solar systems. However, some planetesimals from the zones inside of or directly beyond would later stray into the asteroid belt region and become trapped.

    As those planetesimals collided, the resulting smaller pieces would form what we today observe as asteroids. The simulations are even able to explain the different asteroid populations: What astronomers call S-types asteroids, bodies that are made mostly of silica, would be the remnants of stray objects originating in the region around Mars, while C-type asteroids, which predominantly contain Carbon, would be the remnants of stray objects from the region directly outside the asteroid belt.

    Outer planets and Kuiper belt

    In that outer region, just outside the pressure bump that marks the inner limit for the presence of water ice, the simulations show the beginning of the formations of giant planets – the planetesimals near that boundary typically have a total mass of between 40 and 100 times the mass of the Earth, consistent with estimates of the total mass of the cores of the giant planets in our solar system: Jupiter, Saturn, Uranus and Neptune.

    In that situation, the most massive planetesimals would quickly gather more mass. The present simulations did not follow up on the (already well-studied) later evolution of those giant planets, which involves an initially rather tight group, from which Uranus and Neptune later migrated outwards to their present positions.

    Last but not least, the simulations can explain the final class of objects, and its properties: so-called Kuiper-belt objects, which formed outside the outermost pressure bump, which marks the inner boundary for the existence of carbon monoxide ice.

    Kuiper Belt. Minor Planet Center.

    It even can explain the slight differences in composition between known Kuiper-belt objects: again as the difference between planetesimals that formed originally outside the CO snowline pressure bump and stayed there, and planetesimals that strayed into the Kuiper belt from the adjacent inner region of the giant planets.

    Two basic outcomes and our rare solar system

    Overall, the spread of simulations led to two basic outcomes: Either a pressure bump at the water-ice snowline formed very early; in that case, the inner and outer regions of the planetary system went their separate ways rather early on within the first hundred thousand years. This led to the formation of low-mass terrestrial planets in the inner parts of the system, similar to what happened in our own solar system.

    Alternatively, if the water-ice pressure bump forms later than that or is not as pronounced, more mass can drift into the inner region, leading instead to the formation of Super-Earths or mini-Neptunes in the inner planetary systems. Evidence from the observations of those exoplanetary systems astronomers have found so far shows that case is by far the more probable – and our own Solar system a comparatively rare outcome of planet formation.

    Outlook

    In this research, the focus of the astronomers was on the inner solar system and the terrestrial planets. Next, they want to run simulations that include details of the outer regions, with Jupiter, Saturn, Uranus and Neptune. The eventual aim is to arrive at a complete explanation for the properties of ours and other solar systems.

    For the inner solar system, at least, we now know that key properties of Earth and its nearest neighbouring planet can be traced to some rather basic physics: the boundary between frozen water and water vapour and its associated pressure bump in the swirling disk of gas and dust that surrounded the young Sun.
    Background information

    The results described here have been published in Nature Astronomy.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition


    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] (DE). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard (US), Massachusetts Institute of Technology (US), Stanford (US) and the National Institutes of Health (US)). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences [中国科学院] (CN), the Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

    History
    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
    The Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the Max Planck Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and the DOE’s Argonne National Laboratory (US).
    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
    Max Planck Institutes and research groups
    The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The Max Planck Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
    Internally, Max Planck Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
    In addition, there are several associated institutes:
    International Max Planck Research Schools

    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

     
  • richardmitnick 12:42 pm on November 5, 2021 Permalink | Reply
    Tags: "Tidying up planetary nurseries", , , , , MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) : “Tidying up planetary nurseries” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    November 05, 2021

    Dr. Markus Nielbock
    Press and public relations officer Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-134
    pr@mpia.de MPIA

    Dr. Matías Gárate
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-428
    garate@mpia.de

    Dr. Paola Pinilla
    Research group leader Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-263
    pinilla@mpia.de

    A group of astronomers, led by scientists from the Max Planck Institute for Astronomy, propose and have tested a mechanism that explains most of the properties observed in dispersing planet-forming disks around newborn stars for the first time. The key ingredients to this new physical concept are X-ray emissions from the central star and a calm inner disk, well shielded from the incident radiation. This approach explains the seemingly contradicting features observed in those dwindling transition disks that previous models have been unable to reconcile. This result, published in the journal Astronomy & Astrophysics today, is a big step to understanding the evolution from dusty disks to clean planetary systems like the Solar System.

    1
    Schematic view of a transition disk around a solar-type star. X-ray emission from the central star illuminates the disk. The irradiation ionises the gas in the disk. It gives rise to winds through photoevaporation, which expels the gas into outer space. Eventually, a gap opens and detaches the inner disk from the outer reservoir of gas and dust. A dead zone inside the inner disk prevents the material from rapidly accreting onto the star. This process extends the lifetime of the inner disk and prolongs its accretion activity. © MPIA.

    Planets form inside disks made of gas and dust. Each of those disks already gave birth to a new star, or, for that matter, to a predecessor that still has to ignite its nuclear fusion fire, called a protostar. When we look at the Solar System, we recognise that most of that material has long since disappeared. In recent years, research has reached a basic understanding of how these circumstellar disks lose their remnant gas and dust. With the advent of powerful telescopes, astronomers have even identified and studied those dissolving disks coined transition disks.

    However, identifying the detailed physical processes remained unsuccessful. The theoretical concepts scientists have explored so far only reproduced a few of the observed properties at a time. Now, a research group led by astronomers from the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, proposes a new scheme that overcomes most of the disadvantages of previous approaches. “Earlier models failed to reproduce more than only a few of the observational results of transition disks,” says Matías Gárate, lead author of the underlying scientific article and scientist at MPIA. “However, we are now able to explain most of the properties that seem to contradict each other: a wide gap in the disk and a sustained accretion of gas and dust from a long-lived inner disk onto the central star.”

    Intuitively, it is hard to understand why almost all observed transition disks with a wide gap show signs of accretion. Accretion is the process that feeds the central star with gas and dust from the circumstellar disk. Before the gap opens, material from the thicker outer disk replenishes the inner sectors, sustaining the subsequent transport towards the central star. However, the reservoir is limited, which, in time, reduces the matter flow.

    At the same time, X-ray emission from the star hits and heats the disk surface. The radiation gives rise to a wind that expels the then ionised gas into open space. This process is called photoevaporation. As soon as it is more efficient than the outside-in matter flow in the disk, a gap begins to open and disconnects the inner disk from the outer reservoir. At this point, the inner disk should empty very quickly via accretion and disappear rapidly. Accretion onto the star comes to a halt.

    “We realised that to extend the lifetime of the inner disk and prolong accretion activity, we had to find a mechanism that reduces the inward drift of the gas and the dust,” Paola Pinilla points out, who is the “Genesis of Planets” research group leader at MPIA and a co-author of the paper. “One way of doing this is to include a generally accepted component of circumstellar disks, a so-called dead zone,” Timmy Delage adds, who is a PhD student at MPIA and another co-author of the research article.

    A dead zone is a relatively calm annular region of a circumstellar disk where the random gas motion is reduced compared to other disk components. Consequently, friction between individual particles becomes almost negligible, making it difficult to reduce their orbital velocities, stabilising their orbits. Dead zones may manifest themselves when gas is insufficiently ionised and only poorly affected by magnetic fields. They can occur, for example, when the gas is dense enough to protect the deeper disk layers from ionisation by radiation hitting the disk.

    2
    Comparison between observed and simulated dust distributions in transition disks. Left: Image of the disk around the object CIDA1 at a wavelength of 0.9 mm obtained with the ALMA interferometer as published in Pinilla et al., A&A 649, A122 (2021), DOI: 10.1051/0004-6361/202140371. The disk is slightly tilted with respect to the image plane. Right: Synthetic image of the dust distribution from the simulations performed by Matías Gárate and collaborators. © Pinilla et al./Gárate et al./MPIA.

    To verify if such a dead zone can explain the observational findings of accreting transition disks with wide gaps, Matías Gárate and his colleagues simulated their evolution in time. They constructed a physical disk model while varying the initial conditions for the dead zone and including X-ray irradiation to facilitate photoevaporation. “We were thrilled when we saw the results. A large majority of the simulated transition disks with a wide range of gap sizes retained a detectable accretion flow to the central solar-type star,” Gárate reports. This result demonstrates that dead zones can produce accreting transition disks with wide gaps in large numbers.

    Although the result is a big leap in understanding what astronomers find with telescopes when looking at actual transition disks, it still falls short of reproducing the exact numbers. While observations appear to find approximately 3% of the transition disks to be non-accreting, the simulations produce more than ten times this fraction. Indeed, since computing power is limited, the model used in this study only reflects a simplified version of the real world and does not include all possible mechanisms suspected to occur in such disks. Some of them may even increase the longevity of the inner disk. On the other hand, it is well possible astronomers have to revisit some of their conclusions drawn from observations, and there may actually be more non-accreting disks than previously thought.

    During their study, the MPIA-led team explored the accretion activity by focussing on the gas. Still, the dust can behave quite differently. When astronomers take images of such planet-forming disks, it is often the distribution of the dust they see radiating at millimetre wavelengths, frequently shaped in the form of concentric rings. Therefore, the MPIA astronomers investigated if their simulations also treat the dust realistically.

    “To compare our calculations with highly resolved images of real transitions disks we had obtained with the ALMA interferometer, we produced a synthetic picture of one of the simulated dust disks,” says co-author Jochen Stadler, a master student at MPIA and The Ruprecht Karl University of Heidelberg, [Ruprecht-Karls-Universität Heidelberg] (DE).

    European Southern Observatory/National Radio Astronomy Observatory(US)/National Astronomical Observatory of Japan(JP) ALMA Observatory (CL)

    The result is a stunning confirmation. The image of the computer-generated dust distribution shows the elements typical of transition disks: a small inner disk and an outer ring, both separated by a wide gap.

    As often, the devil is in the details. While the structures appear to be a good match, the brightnesses disagree. The dust emission of the simulated transition disks is considerably fainter than one would expect from observations. Hence, the synthetic disks probably possess less dust than the real ones. However, the authors have a reasonable solution for this discrepancy. “We think this is a consequence of planet formation we have not included in our models,” Gárate points out. Studies frequently show that newly formed planets carve gaps along their orbits through the disk. Such rifts function like barriers for the dust drifting radially. Gárate adds: “It is well possible the planetary gaps escape detection by observation due to insufficient spatial resolution. If planets form in the inner disk, that may help prevent dust from accreting onto the central star. We will extend our models accordingly and explore if we can also solve this puzzle.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition


    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] (DE). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard (US), Massachusetts Institute of Technology (US), Stanford (US) and the National Institutes of Health (US)). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences [中国科学院] (CN), the Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

    History
    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
    The Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the Max Planck Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and the DOE’s Argonne National Laboratory (US).
    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
    Max Planck Institutes and research groups
    The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The Max Planck Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
    Internally, Max Planck Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
    In addition, there are several associated institutes:
    International Max Planck Research Schools

    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

     
  • richardmitnick 11:27 am on September 23, 2021 Permalink | Reply
    Tags: "How to weigh a quasar", , , , BLR: “broad emission-line region” - a zone in which ionised gas clouds orbit the central black hole at speeds of several thousand kilometres per second., MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), Quasars contain supermassive black holes in the centres of galaxies and are among the brightest cosmic objects., Quasars: beacons of the Universe, RM: “Reverberation Mapping” - this method has decisive disadvantages compared to spectroastrometry., Spectroastrometry   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) : “How to weigh a quasar” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    September 22, 2021

    Dr. Markus Nielbock
    Press and public relations officer
    Tel +49 6221 528-134
    pr@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Dr. Felix Bosco
    Tel +49 6221 528-347
    bosco@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Dr. Jörg-Uwe Pott
    Tel +49 6221 528-202
    jpott@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Testing a new, direct method for determining the masses of supermassive black holes.

    Astronomers of the Max Planck Institute for Astronomy have, for the first time, successfully tested a new method for determining the masses of extreme black holes in quasars. This method is called spectroastrometry and is based on the measurement of radiation emitted by gas in the vicinity of supermassive black holes. This measurement simultaneously determines the rotational velocity of the radiating gas and its distance from the centre of the accretion disk from which material flows into the black hole. Compared to other methods, spectroastrometry is relatively straightforward and efficient if performed with modern large telescopes. The high sensitivity of this method permits investigating the surroundings of luminous quasars and supermassive black holes in the early Universe.

    1
    Schematic representation of a quasar. The hot accretion disk in the centre surrounds the black hole, which is invisible here. A dense distribution of gas and dust surrounds it in which individual ionised gas clouds orbit the black hole at high speed. Stimulated by the intense and high-energy radiation of the accretion disk, these clouds emit radiation in the form of spectral lines, broadened due to the Doppler effect. The zone of these gas clouds is therefore called broad emission-line region (BLR). Image: Bosco/Graphics department/MPIA.

    In cosmology, determining the mass of supermassive black holes in the young Universe is an important measurement for tracking the temporal evolution of the cosmos. Now Felix Bosco, in close collaboration with Jörg-Uwe Pott, both from the Max Planck Institute for Astronomy (MPIA) in Heidelberg, and former MPIA researchers Jonathan Stern (now Tel Aviv University (IL)) and Joseph Hennawi (now The University of California-Santa Barbara (US) and Leiden University [Universiteit Leiden] (NL)), has succeeded for the first time in demonstrating the feasibility of directly determining the mass of a quasar using spectroastrometry.

    This method allows the mass of distant black holes in luminous quasars to be determined directly from optical spectra, without the need for extensive assumptions about the spatial distribution of gas. The spectacular applications of spectroastrometric measurements of quasar masses were systematically investigated at MPIA several years ago.

    Quasars: beacons of the Universe

    Quasars contain supermassive black holes in the centres of galaxies and are among the brightest cosmic objects. Therefore, they are detectable over large distances and thus enable the exploration of the early Universe.

    If there is gas near a black hole, it cannot fall into it directly. Instead, an accretion disk forms, a vortex that helps the matter flow into the black hole. High frictional forces in this stream of gas, which ultimately feeds the black hole, heat the accretion disk typically to fifty thousand degrees. The intensity of the radiation emitted in the process makes the quasars appear so bright that they outshine all the stars in the galaxy.

    Other components within quasars have been known for several decades, such as the so-called “broad emission-line region” (BLR), a zone in which ionised gas clouds orbit the central black hole at speeds of several thousand kilometres per second. The intense and energetic radiation from the accretion disk stimulates emission from the gas in the BLR, which is visible in the spectra in the form of spectral lines. However, due to the Doppler effect, they are strongly broadened by the high orbital velocities, thus giving the BLR its name.

    3
    Schematic representation of the origin of the spectroastrometry signal. If the ionised gas were at rest, we would measure the same wavelength of the spectral line throughout the BLR. However, the gas clouds orbit the black hole. Seen from the side, they come towards us on one side while they move away again on the other. As a result, the spectral signal appears blue-shifted towards shorter wavelengths on one side. On the other side, it is red-shifted towards longer wavelengths. This difference in the measured wavelength depending on the position along the BLR results in the spectroastrometry signal indicated above. From this, researchers can determine the maximum distance of the observed BLR clouds from the centre of the quasar and the prevailing velocity there. Image: Bosco/Graphics department/MPIA.

    A new method of measuring black hole masses

    Now, Felix Bosco and his colleagues have measured the optically brightest spectral line of hydrogen (Hα) in the BLR of the quasar J2123-0050 in the constellation Aquarius. Its light stems from a time when the Universe was just 2.9 billion years old. Using the method of spectroastrometry, they have determined the putative distance of the radiation source in the BLR to the centre of the accretion disk, the location of the potential supermassive black hole. At the same time, the Hα line provides the radial velocity of the hydrogen gas, i.e., that velocity component that points towards Earth. Just as the mass of the Sun determines the orbital velocities of the planets in the solar system, the mass of the black hole at the centre of the quasar can be precisely deduced from this data if the gas distribution can be spatially resolved.

    Even for today’s large telescopes, however, the extent of the BLR is far too small for this. “However, by separating spectral and spatial information in the collected light, as well as by statistically modelling the measured data, we can derive distances of much less than one image pixel from the centre of the accretion disk,” Felix Bosco explains. The duration of the observations determines the precision of the measurement.

    For J2123-0050, the astronomers calculated a black hole mass of at most 1.8 billion solar masses. “The exact mass determination was not yet the main goal of these first observations at all,” says Jörg-Uwe Pott, co-author and head of the “Black Holes and Accretion Mechanisms” working group at MPIA. “Instead, we wanted to show that the spectroastrometry method can in principle detect the kinematic signature of the central quasar masses using the 8-metre telescopes already available today.”

    Spectroastrometry could thus be a valuable addition to the tools that researchers use to determine black hole masses. Joe Hennawi adds, “With the significantly increased sensitivity of the James Webb Space Telescope (JWST) and the Extremely Large Telescope (ELT with a primary mirror diameter of 39 metres) currently under construction, we will soon be able to determine quasar masses at the highest redshifts.”

    Jörg-Uwe Pott, who also leads the Heidelberg contributions to ELT’s first near-infrared camera, MICADO, adds, “The feasibility study now published helps us to define and prepare our planned ELT research programmes.”

    Spectroastrometry valuable addition to classical methods

    Among the alternatives for surveying BLR in nearby quasars is a widely used method: “Reverberation Mapping” (RM). It employs the light transit time any brightness fluctuation in the accretion disk needs to excite the surrounding gas to increased radiation. From this, astronomers estimate the mean extent of the BLR. Besides the sometimes considerable uncertainties in the assumptions, this method has decisive disadvantages compared to spectroastrometry when investigating the most massive and distant black holes. The diameter of the BLR correlates with the mass of the central black hole. Hence, the signal delay between the accretion disk and the BLR becomes very large for massive black holes in the early Universe. The necessary series of measurements of several years become impractically long.

    Moreover, the brightness fluctuations and measurability tend to decrease with increasing black hole mass and quasar luminosity. The RM method is, therefore, rarely applicable to luminous quasars. As a result, it is not suitable for measuring quasars at large cosmological distances.

    However, the RM serves as a basis for calibrating other indirect methods first established for nearby quasars and then extended to more distant, luminous quasars with massive black holes. The quality of these indirect approaches stands and falls with the accuracy of the RM method. Here, too, spectroastrometry can help put the mass determination of massive black holes on a broader basis. For example, evaluating the data from J2123-0050 indicates that the correlation between the size of the BLR and the quasar luminosity, initially established with the RM method for rather close, faint quasars, actually seems to hold for luminous quasars as well. However, further measurements are needed here.

    The BLR can also be measured interferometrically in nearby active galaxies, such as with the GRAVITY instrument of the Very Large Telescope Interferometer (VLTI).

    The great advantage of spectroastrometry, however, is that only a single highly-sensitive observation is needed. In addition, it requires neither the technically very complex coupling of several telescopes as required by interferometry nor long series of measurements over months and years as is the case with the RM. For example, a single series of observations with an exposure time of four hours with the 8-metre-class Gemini North telescope in Hawaii, supported by a correction system consisting of a laser guide star and adaptive optics, was sufficient for the research group led by Felix Bosco.

    Opening a new door to the exploration of the early Universe

    Researchers have high hopes for the next generation of large optical telescopes such as ESO’s ELT. Combining an enlarged light-collecting surface with fivefold increased image sharpness would make the observation presented here possible in just a few minutes at the ELT. Felix Bosco explains, “We will use the ELT to astrometrically measure numerous quasars at different distances in a single night, allowing us to observe the cosmological evolution of black hole masses directly.” With the successful astrometric feasibility study, the authors have pushed wide open a new door to the exploration of the early Universe.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] (DE). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard (US), Massachusetts Institute of Technology (US), Stanford (US) and the National Institutes of Health (US)). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences [中国科学院] (CN), the Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

    History
    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
    The Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the Max Planck Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and the DOE’s Argonne National Laboratory (US).
    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
    Max Planck Institutes and research groups
    The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The Max Planck Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
    Internally, Max Planck Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
    In addition, there are several associated institutes:
    International Max Planck Research Schools

    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

     
  • richardmitnick 10:00 pm on June 14, 2021 Permalink | Reply
    Tags: "Black holes help with star birth", Cosmic mass monsters clear the way for the formation of new suns in satellite galaxies., MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), , , Women in STEM-Annalisa Pillepich   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) : Women in STEM-Annalisa Pillepich “Black holes help with star birth” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    June 09, 2021

    Markus Pössel
    Head of press and public relations
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-261
    pr@mpia.de
    Annalisa Pillepich
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-395
    pillepich@mpia.de

    The cosmic mass monsters clear the way for the formation of new suns in satellite galaxies.

    Research combining systematic observations with cosmological simulations has found that, surprisingly, black holes can help certain galaxies form new stars. On scales of galaxies, the role of supermassive black holes for star formation had previously been seen as destructive – active black holes can strip galaxies of the gas that galaxies need to form new stars. The new results, published in the journal Nature, showcase situations where active black holes can, instead, “clear the way” for galaxies that orbit inside galaxy groups or clusters, keeping those galaxies from having their star formation disrupted as they fly through the surrounding intergalactic gas.

    1
    Virtual milky way: Gas density around a massive central galaxy in a group in the virtual universe of the TNG50 simulation. Gas inside the galaxy corresponds to the bright vertical structure: a gaseous disk. To the left and right of that structure are bubbles – regions that look like circles in this image, with markedly reduced gas density inside. This geometry of the gas is due to the action of the super massive black hole that hides at the center of the galaxy and that pushes out gas preferably in directions perpendicular to the galaxy gaseous disk, carving regions of lower density. © Dylan Nelson/TNG Collaboration.

    Active black holes are primarily thought to have a destructive influence on their surroundings. As they blast energy into their host galaxy, they heat up and eject that galaxy’s gas, making it more difficult for the galaxy to produce new stars. But now, researchers have found that the same activity can actually help with star formation – at least for the satellite galaxies that orbit the host galaxy.

    The counter-intuitive result came out of a collaboration sparked by a lunchtime conversation between astronomers specializing in large-scale computer simulations and observers. As such, it is a good example for the kind of informal interaction that has become more difficult under pandemic conditions.

    Astronomical observations that include taking a distant galaxy’s spectrum – the rainbow-like separation of a galaxy’s light into different wavelengths – allow for fairly direct measurements of the rate at which that galaxy is forming new stars.

    Going by such measurements, some galaxies are forming stars at rather sedate rates. In our own Milky Way galaxy, only one or two new stars are born each year. Others undergo brief bursts of excessive star formation activity, called “star bursts”, with hundreds of stars born per year. In yet other galaxies, star formation appears to be suppressed, or “quenched,” as astronomers say: Such galaxies have virtually stopped forming new stars.

    A special kind of galaxy, specimens of which are frequently – almost half of the time – found to be in such a quenched state, are so-called satellite galaxies. These are part of a group or cluster of galaxies, their mass is comparatively low, and they orbit a much more massive central galaxy similar to the way satellites orbit the Earth.

    Such galaxies typically form very few new stars, if at all, and since the 1970s, astronomers have suspected that something very much akin to headwind might be to blame: Groups and clusters of galaxies not only contain galaxies, but also rather hot thin gas filling the intergalactic space.

    As a satellite galaxy orbits through the cluster at a speed of hundreds of kilometers per second, the thin gas would make it feel the same kind of “headwind” that someone riding a fast bike, or motor-bike, will feel. The satellite galaxy’s stars are much too compact to be affected by the steady stream of oncoming intergalactic gas.

    But the satellite galaxy’s own gas is not: It would be stripped away by the oncoming hot gas in a process known as “ram pressure stripping”. On the other hand, a fast-moving galaxy has no chance of pulling in a sufficient amount of intergalactic gas, to replenish its gas reservoir. The upshot is that such satellite galaxies lose their gas almost completely – and with it the raw material needed for star formation. As a result, star-formation activity would be quenched.

    The processes in question take place over millions or even billions of years, so we cannot watch them happening directly. But even so, there are ways for astronomers to learn more. They can utilize computer simulations of virtual universes, programmed so as to follow the relevant laws of physics – and compare the results with what we actually observe. And they can look for tell-tale clues in the comprehensive “snapshot” of cosmic evolution that is provided by astronomical observations.

    Annalisa Pillepich, a group leader at the MPG Institute for Astronomy [MPG Institut für Astronomie](DE), specializes in simulations of this kind. The IllustrisTNG suite of simulations, which Pillepich has co-led, provides the most detailed virtual universes to date – universes in which researchers can follow the movement of gas around on comparatively small scales.

    IllustrisTNG provides some extreme examples of satellite galaxies that have freshly been stripped by ram pressure: so-called “jellyfish galaxies,” that are trailing the remnants of their gas like jellyfish are trailing their tentacles. In fact, identifying all the jellyfish in the simulations is a recently launched citizen science project on the Zooniverse platform, where volunteers can help with the research into that kind of freshly quenched galaxy.

    But, while jellyfish galaxies are relevant, they are not where the present research project started. Over lunch in November 2019, Pillepich recounted a different one of her IllustrisTNG results to Ignacio Martín-Navarro, an astronomer specializing in observations, who was at MPIA on a Marie Curie fellowship. A result about the influence of supermassive black holes that reached beyond the host galaxy, into intergalactic space.

    Such supermassive black holes can be found in the center of all galaxies. Matter falling onto such a black hole typically becomes part of a rotating so-called accretion disk surrounding the black hole, before falling into the black hole itself. This fall onto the accretion disk liberates an enormous amount of energy in the form of radiation, and oftentimes also in the form of two jets of quickly moving particles, which accelerate away from the black hole at right angles to the accretion disk. A supermassive black hole that is emitting energy in this way is called an Active Galactic Nucleus, AGN for short.

    While IllustrisTNG is not detailed enough to include black hole jets, it does contain physical terms that simulate how an AGN is adding energy to the surrounding gas. And as the simulation showed, that energy injection will lead to gas outflows, which in turn will orient themselves along a path of least resistance: in the case of disk galaxies similar to our own Milky Way, perpendicular to the stellar disk; for so-called elliptical galaxies, perpendicular to a suitable preferred plane defined by the arrangement of the galaxy’s stars.

    Over time, the bipolar gas outflows, perpendicular to the disk or preferred plane, will go so far as to affect the intergalactic environment – the thin gas surrounding the galaxy. They will push the intergalactic gas away, each outflow creating a gigantic bubble. It was this account that got Pillepich and Martín-Navarro thinking: If a satellite galaxy were to pass through that bubble – would it be affected by the outflow, and would its star formation activity be quenched even further?

    Martín-Navarro took up this question within his own domain. He had extensive experience in working with data from one of the largest systematic surveys to date: the Sloan Digital Sky Survey (SDSS), which provides high-quality images of a large part of the Northern hemisphere. In the publicly available data from that survey’s 10th data, he examined 30,000 galaxy groups and clusters, each containing a central galaxy and on average 4 satellite galaxies.

    In a statistical analysis of those thousands of systems, he found a small, but marked difference between satellite galaxies that were close to the central galaxy’s preferred plane and satellites that were markedly above and below. But the difference was in the opposite direction the researchers had expected: Satellites above and below the plane, within the thinner bubbles, were on average not more likely, but about 5% less likely to have had their star formation activity quenched.

    With that surprising result, Martín-Navarro went back to Annalisa Pillepich, and the two performed the same kind of statistical analysis in the virtual universe of the IllustrisTNG simulations. In simulations of that kind, after all, cosmic evolution is not put in “by hand” by the researchers. Instead, the software includes rules that model the rules of physics for that virtual universe as naturally as possible, and which also include suitable initial conditions that correspond to the state of our own universe shortly after the Big Bang.

    That is why simulations like that leave room for the unexpected – in this particular case, for re-discovering the on-plane, off-plane distribution of quenched satellite galaxies: The virtual universe showed the same 5% deviation for the quenching of satellite galaxies! Evidently, the researchers were on to something.

    In time, Pillepich, Martín-Navarro and their colleagues came up with a hypothesis for the physical mechanism behind the quenching variation. Consider a satellite galaxy travelling through one of the thinned-out bubbles the central black hole has blown into the surrounding intergalactic medium. Due to the lower density, that satellite galaxy experiences less headwind, less ram pressure, and is thus less likely to have its gas stripped away.

    Then, it is down to statistics. For satellite galaxies that have orbited the same central galaxies several times already, traversing bubbles but also the higher-density regions in between, the effect will not be noticeable. Such galaxies will have lost their gas long ago.

    But for satellite galaxies that have joined the group, or cluster, rather recently, location will make a difference: If those satellites happen to land in a bubble first, they are less likely to lose their gas then if they happen to land outside a bubble. This effect could account for the statistical difference for the quenched satellite galaxies.

    With the excellent agreement between the statistical analyses of both the SDSS observations and the IllustrisTNG simulations, and with a plausible hypothesis for a mechanism, this is a highly promising result. In the context of galaxy evolution, it is particularly interesting because it confirms, indirectly, the role of active galactic nuclei not only heating intergalactic gas up, but actively “pushing it away”, to create lower-density regions. And as with all promising results, there are now a number of natural directions that either Martín-Navarro, Pillepich and their colleagues or other scientists can take in order to explore further.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Max Planck Institute for Astronomy, Heidelburg, GE

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.
    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.
    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard, MIT, Stanford and the US NIH). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences, the Russian Academy of Sciences and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.
    The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.
    History
    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
    The Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the Max Planck Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and the DOE’s Argonne National Laboratory (US).
    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
    Max Planck Institutes and research groups
    The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The Max Planck Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
    Internally, Max Planck Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
    In addition, there are several associated institutes:

    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

     
  • richardmitnick 12:51 pm on June 2, 2021 Permalink | Reply
    Tags: "Help astronomers find rare cosmic jellyfish galaxies in this new Zooniverse citizen science project!", A rare kind of galaxy is at the heart of a new citizen science project that is being unveiled today: "Cosmological Jellyfish"., , , , , , MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE) : “Help astronomers find rare cosmic jellyfish galaxies in this new Zooniverse citizen science project!” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    June 01, 2021

    Markus Pössel
    Head of press and public relations
    +49 6221 528-261
    pr@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Annalisa Pillepich
    +49 6221 528-395
    pillepich@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Gandhali Joshi
    +49 6221 528-370
    joshi@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Help astronomers find rare cosmic jellyfish galaxies in this new Zooniverse citizen science project!

    A rare kind of galaxy is at the heart of a new citizen science project that is being unveiled today: “Cosmological Jellyfish” is part of the Zooniverse platform, where volunteers can contribute to genuine scientific research projects.

    5
    https://blog.zooniverse.org/2020/03/18/zooniverse-remote-online-learning-resources/

    In the new project, participants look at the results of a cosmological simulation and identify galaxies that look somewhat like jellyfish. The jellyfish-like appearance is an indicator that the galaxy in question has interacted with gas in a galaxy cluster – which is what the creators of the project, the group of Annalisa Pillepich at the Max Planck Institute for Astronomy, want to study further.

    1
    Eight examples for jellyfish galaxies. Images like these are presented to the participants of the new Zooniverse project for classification. Credit: IllustrisTNG collaboration

    Galaxies like our own Milky Way galaxy, consisting of millions, billions or even hundreds of billions of stars, are large-scale building blocks of our universe. While astronomers are confident they now have a reliable overall picture of how galaxies have formed over the past 13.8 billion years, after the hot Big Bang phase of the universe, many details are still in need of further research – and whenever new observations and powerful simulations become available, there are opportunities of adding pieces to the puzzle.

    One region of the puzzle that is badly in need of more pieces is the case of so-called jellyfish galaxies.

    4
    Located 220 million light-years away, this jellyfish galaxy migrates toward one o’clock. Credit: COURTESY OF HUBBLE SPACE TELESCOPE, NASA, ESA AND HUBBLE HERITAGE TEAM (STScI/AURA); ACKNOWLEDGMENT: M. SUN University of Alabama in Huntsville.
    https://hubblesite.org/
    https://www.nasa.gov/
    http://www.esa.int/esaCP/index.html
    http://www.stsci.edu/portal/
    http://www.aura-astronomy.org/
    https://www.uah.edu/

    Such galaxies can be found in galaxy clusters, alongside with thousands of other galaxies. Such clusters not only contain the galaxies themselves, but also thin, hot intergalactic gas. As thin as that gas is, it is enough to make galaxies that are moving at high velocities through the cluster feel a “headwind”.

    The missing details of jellyfish formation

    Imagine someone on a motor bike, with their hair, or maybe their shawl, streaming behind as they move through the surrounding air. Galaxies moving quickly through a cluster feel a similar headwind, or “ram pressure”. The stars in such a galaxy are virtually unaffected, but in extreme cases, the gas that is contained in the galaxy can be driven out, streaming behind the galaxy. The result is a galaxy that looks similar to a jellyfish: a body (made up of the galaxy’s stars) with tentacles (gas) streaming behind.

    We have yet to understand how this works in detail, though: Do such jellyfish galaxies form only in the most massive clusters, or can they form even around our own Milky Way? Where and how quickly do the tails form and how long do they last? What happens to the gas in these tails? How does the stripping process affect the galaxies themselves?

    Computer simulations to the rescue

    Since the processes in question occur over hundreds of millions or even billions of years, it is impossible for us to observe them happening in the Universe in real time. But we can turn to computer simulations to find out more! Cosmological simulations create a virtual universe following the same laws of physics as our own cosmos. In that model universe, virtual stars and galaxies form, interact, and evolve – and for each galaxy, one can reconstruct its history!

    A key problem here are the hugely disparate scales. The physics of how stars evolve takes place on scales of thousands of kilometers. A half-way representative volume of cosmic space is hundreds of millions of light-years across, a factor of one quintillion (one with 18 zeros) larger! No computer simulation has yet managed to simulate individual stars in such a cosmological volume. But for a few years now, there have been simulations that manage to model galaxies in sufficient detail for the simulation to capture ram-pressure in clusters, and the way it can turn galaxies into jellyfish galaxies.

    Tracking jellyfish in IllustrisTNG

    3
    (c) 2021 The TNG Collaboration.

    The first simulations that have managed to capture jellyfish creation are part of a suite called IllustrisTNG. There are three different versions of the IllustrisTNG simulation, each with a different size of the cosmic volume, a different resolution, and containing thousands to hundreds of thousands of galaxies. The two higher-resolution versions of the simulation, known as TNG50 and TNG100, are sufficiently detailed to allow for the formation of jellyfish galaxies.

    But in order to study those simulated jellyfish galaxies, the researchers need to determine which of the tens of thousands of galaxies in their virtual universe are jellyfish galaxies in the first place! This requires a process that is still very difficult for computers to do automatically – but comparatively simple for human brains, with their excellent pattern recognition skills. That is why, as a first step, the researchers set out to learn which of their simulated galaxies look like jellyfish to a human observer, with a body made of stars trailing a tail made of gas.

    Crowdsourcing jellyfish-galaxy identification

    In a pilot study, led by Kiyun Yun, one of the group’s PhD students, the team members themselves identified by eye 800 jellyfish galaxies among 2600 pre-selected candidates. But that is only a fraction of the available data – and looking at all the data in this fashion is more than a small team of scientists can handle.

    This is where the Zooniverse comes in: the world’s largest and most popular platform for people-powered research, which specializes in exactly this kind of citizen science: projects where human volunteers and their pattern-recognition-savvy brains can contribute to cutting-edge scientific research. Parsing through 38,000 images in search of rare galaxies is a considerable task, but not that difficult if thousands of volunteers take it on.

    Building on work by Yun and another group member Elad Zinger, now at the Hebrew University of Jerusalem, post-doctoral researcher Gandhali Joshi transformed the problem of jellyfish galaxy identification into the Zooniverse project that is now being revealed: Cosmological Jellyfish.

    Kickstarting jellyfish galaxy research

    In the project, participants study pictures, each of which shows a galaxy in the middle of the image. Each picture was created from the TNG50 and TNG100 simulations, and shows a particular galaxy viewed from a random angle, along with any other gas and galaxies contained in that region Participants then need to decide: Does that particular galaxy look like a jellyfish or not?

    While the project provides a tutorial, as well as classification feedback for some of the images, nature is messy – even faithfully simulated nature. There will always be cases where it is difficult to decide whether or not a specific galaxy resembles a jellyfish. But in the end, it’s OK to be uncertain: During the project, each galaxy will be classified by at least twenty different participants. In the end, researchers will be able to distinguish galaxies that clearly are, or are not, jellyfish galaxies from more ambiguous specimens (where some participants saw jellyfish, others not).

    Once the jellyfish galaxies are identified, the researchers know which galaxies in their simulated universe they will need to look at more closely. The simulation provides the complete formation history for each galaxy, so at that stage, the scientists should be able to find out how these galaxies were formed, how they evolved to look like jellyfish in the first place – and what went differently for the galaxies that do not look like jellyfish!

    Links

    The Cosmological Jellyfish project is available in English, in German and in Hebrew at

    https://www.zooniverse.org/projects/apillepich/cosmological-jellyfish

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Max Planck Institute for Astronomy, Heidelburg, GE

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.
    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.
    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard, MIT, Stanford and the US NIH). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences, the Russian Academy of Sciences and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.
    The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.
    History
    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.
    The Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the Max Planck Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and the DOE’s Argonne National Laboratory (US).
    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.
    Max Planck Institutes and research groups
    The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The Max Planck Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.
    Internally, Max Planck Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.
    In addition, there are several associated institutes:

    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:
    Cologne Graduate School of Ageing Research, Cologne
    International Max Planck Research School for Intelligent Systems, at the MPG Institute for Intelligent Systems (DE) located in Tübingen and Stuttgart
    International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPG for Astronomy
    International Max Planck Research School for Astrophysics, Garching at the MPG Institute for Astrophysics
    International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    International Max Planck Research School for Computer Science, Saarbrücken
    International Max Planck Research School for Earth System Modeling, Hamburg
    International Max Planck Research School for Elementary Particle Physics, Munich, at the MPG Institute for Physics
    International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the MPG Institute for Terrestrial Microbiology
    International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    International Max Planck Research School “From Molecules to Organisms”, Tübingen at the MPG Institute for Developmental Biology
    International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPG Institute for Gravitational Physics
    International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the MPG Institute for Heart and Lung Research
    International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    International Max Planck Research School for Language Sciences, Nijmegen
    International Max Planck Research School for Neurosciences, Göttingen
    International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    International Max Planck Research School for Marine Microbiology (MarMic), joint program of the MPG Institute for Marine Microbiology in Bremen, the University of Bremen (DE), the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    International Max Planck Research School for Maritime Affairs, Hamburg
    International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    International Max Planck Research School for Molecular and Cellular Life Sciences, Munich[
    International Max Planck Research School for Molecular Biology, Göttingen
    International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster (DE) and the MPG Institute for Molecular Biomedicine (DE)
    International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    International Max Planck Research School for Organismal Biology, at the University of Konstanz (DE) and the MPG Institute for Ornithology (DE)
    International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion (DE)
    International Max Planck Research School for Science and Technology of Nano-Systems, Halle at MPG Institute of Microstructure Physics (DE)
    International Max Planck Research School for Solar System Science[49] at theUniversity of Göttingen – Georg-August-Universität Göttingen (DE) hosted by MPG Institute for Solar System Research [Max-Planck-Institut für Sonnensystemforschung] (DE)
    International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at MPG Institute for Iron Research [MPG Institut für Eisenforschung] (DE)
    International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

     
  • richardmitnick 10:54 pm on January 28, 2021 Permalink | Reply
    Tags: "When dwarfs give birth to giants", A new exoplanet that should not exist according to current knowledge., , , , CARMENES consortium, , MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), , The gas giant called GJ 3512 b together with its mother star GJ 3512.   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE): “When dwarfs give birth to giants” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    September 26, 2019 (Brought foward by MPIA)

    Prof. Dr. Hubert Klahr
    Head of Theory Group “Planet- and Star Formation”
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 5328-255
    klahr@mpia.de

    Diana Kossakowski
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 5328-286
    kossakowski@mpia.de

    Dr Markus Nielbock
    Press and public relations officer
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 5328-134
    pr@mpia.de

    Astronomers of the CARMENES consortium have discovered a new exoplanet that should not exist according to current knowledge. The research group, which includes the Max Planck Institute for Astronomy (MPIA, Heidelberg), found a gaseous planet whose mass is unusually large compared to its host star GJ 3512. The scientists conclude that this planet probably originated from a gravitationally unstable disk of gas and dust around the then still young dwarf star. This contradicts the currently, widely accepted model of planet formation, which requires a solid core to collect surrounding gas.

    Astronomers are certain that planets are a by-product from the process of star formation. They form in the disk from which their parent star also emerged. The predominant model for the formation of planets is based on the notion that an object initially develops from solid particles in the disk. The gravitational pull of this planetary embryo ensures that an atmosphere is formed from the surrounding gas.

    Now scientists of the CARMENES consortium led by Juan Carlos Morales, a researcher from the Institute of Space Studies of Catalonia (ES) (IEEC) at the Institute of Space Sciences (ICE, CSIC), with contributions from Diana Kossakowski and Hubert Klahr (MPIA) have discovered a gas planet similar to Jupiter that contradicts this model. Instead, it seems to have developed directly out of the disk, without a solid nucleus of condensation.

    1
    Comparison of GJ 3512 to the Solar System and other nearby red-dwarf planetary systems. Planets around solar-mass stars can grow until they start accreting gas and become giant planets such as Jupiter, in a few millions of years. However, up to now astronomers suspected that, except for some rare exceptions, small stars such as Proxima, TRAPPIST-1, Teegardern’s star, and GJ 3512 were not able to form Jupiter mass planets. © Guillem Anglada-Escude – IEEC/Science Wave, using SpaceEngine.org (Creative Commons Attribution 4.0 International; CC BY 4.0.

    This gas giant, called GJ 3512 b, together with its mother star GJ 3512, is only 9.5 parsecs (30 light years) away from the Sun and has a mass of at least half of that of Jupiter. It takes 204 days for this planet to complete one orbit. Considering the planet on its own, GJ 3512 b is not unusual – but the fact that it is orbiting a red dwarf star makes this planet special. GJ 3512 has only 12% of the mass of the Sun, so the maximum mass ratio between the star and the planet is 270. In comparison, the Sun is about 1050 times heavier than Jupiter. This detail causes headaches for theoretical physicists. The gas and dust disks from which low-mass stars like GJ 3512 evolve should contain rather little material. In fact, too little, as the models show, to be able to even create planetary embryos that could grow into gas giants such as GJ 3512 b itself.

    “One way out would be a very massive disk that has the necessary building blocks in sufficient quantity,” explains Hubert Klahr, who heads a working group on the theory of planet formation at the MPIA. However, if a disk of gas and dust around a star has more than about 1/10 of the stellar mass, the gravitational effect of the star is no longer sufficient to keep the disk stable. The gravity of the disk material itself becomes noticeable and significant. The result is then a gravitational collapse as it happens during star formation. However, such mentioned massive disks have not yet been observed around young dwarf stars.

    The situation gets even more difficult because there is evidence for yet another planet in a long-term orbit around GJ 3512. In addition to these two planets, the strongly elliptical orbit of GJ 3512 b suggests that it was once under the gravitational influence of a possible third planet of similar mass. However, this presumed third planet must have obviously been ejected from the planetary system. This means that in addition to the disk mass required to produce GJ 3512 b, there must have been significantly more matter to create the conditions for the formation of one or even two more planets. This is well outside the boundaries of current stellar and planetary formation models.

    Thus, the researchers of MPIA, the University of Lund in Sweden and the University of Bern (SE), who deal with the simulation of the formation of planets, concluded that the core accretion model fails to explain the existence of GJ 3512 b. Therefore, they have investigated the conditions under which the up to now rather neglected scenario of gravitational disk collapse could indeed lead to the formation of a planet such as GJ 3512 b.

    Using different approaches, they arrived to the same conclusion that GJ 3512 b could have been formed by this process. The regions in the disk beyond 10 au (1 au = 1 astronomical unit: the distance between Earth and Sun) of the central star are very cold with temperatures at about 10 K (-263 °C). There, the thermal pressure cannot compensate for the gravitational effect of the material, so that it collapses under its own weight. Subsequently, the young planet must have migrated over long distances to its current position at a distance well below 1 au from its parent star. This, in turn, is compatible with the current models for the development of planetary systems.

    GJ 3512 b was discovered with the CARMENES spectrograph using the radial velocity method.

    CARMENES spectrograph, mounted on the Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres.


    Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres.

    Radial velocity Image via SuperWasp http http://www.superwasp.org-exoplanets.htm


    Radial Velocity Method-Las Cumbres Observatory, a network of astronomical observatories, located at both northern and southern hemisphere sites distributed in longitude around the Earth.

    CARMENES records spectra in both visible and infrared light. “Red dwarf stars like GJ 3512 show very active behaviour and generate signals similar to those of planets,” explains Diana Kossakowski (MPIA), who was instrumental in the evaluation and the analysis of the data. “The infrared spectra were then important to confirm that what we found is indeed a planet.”

    “Until now, the only planets whose formation was compatible with disk instabilities were a handful of young, hot and very massive planets far away from their host stars,” Hubert Klahr points out. “With GJ 3512 b, we now have an extraordinary candidate for a planet that could have emerged from the instability of a disk around a star with very little mass. This find prompts us to review our models.”

    Science paper:
    Size and structures of disks around very low mass stars in the Taurus star-forming region
    Astronomy & Astrophysics

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Max Planck Institute for Astronomy, Heidelburg, GE

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

     
  • richardmitnick 10:23 pm on January 28, 2021 Permalink | Reply
    Tags: "Peering inside the birthplaces of planets orbiting the smallest stars", Astronomers only know little about the processes that form planets in the disks made of gas and dust surrounding them at a young age., , , , , MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), , To date astronomers have found about 4400 planets in more than 3200 planetary systems around stars other than the Sun., VLMS-very low-mass stars like GJ 3512.   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE): “Peering inside the birthplaces of planets orbiting the smallest stars” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    January 28, 2021

    Nicolas Kurtovic
    Phone:+49 6221 528-474
    kurtovic@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Dr. Paola Pinilla
    Phone:+49 6221 528-263
    pinilla@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Dr. Markus Nielbock
    Press and public relations officer
    Phone:+49 6221 528-134
    pr@mpia.de
    Max Planck Institute for Astronomy, Heidelberg

    Astronomers detect ring structures in the planet forming disks of young, very low-mass stars.

    1
    Artistic representation of a planet-forming disk of dust and gas around a very low-mass star (VLMS). The inner dust disk contains a ring structure that indicates the formation of a new planet. The dust disk resides inside a larger gas disk whose thickness increases towards the edge. Credit: MPIA graphics department.

    To date, astronomers have found about 4400 planets in more than 3200 planetary systems around stars other than the Sun. These numbers are biased, because only about 10% of the known exoplanets orbit so-called Red Dwarfs, although these stars make up for roughly three-quarters of the stellar population in the Milky Way. Red Dwarfs are the least massive, smallest and coolest stars that exist. They are extremely faint compared to most known planet harbouring stars, making them very hard to capture and investigate.

    For all the same reasons, astronomers only know little about the processes that form planets in the disks made of gas and dust surrounding them at a young age. To improve our understanding, a team led by Nicolas Kurtovic, a PhD student at the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, has now mapped and analysed six such disks around young very low-mass stars (VLMS) with unprecedented detail. VLMS are stars with masses of less than 20% of that of our Sun.

    “Despite the tremendous progress in understanding planet formation during recent decades, we don’t know much on how the planets of the most common stars form,” Kurtovic points out. Especially the detection of Jupiter-type planets in orbit around VLMS like GJ 3512 is puzzling and defies the commonly accepted paradigm of planet formation. Their circumstellar disks, from which the planets emerge, only have comparably small amounts of material, making it difficult to form such massive planets.

    The researchers used the Atacama Large Millimeter/submillimeter Array (ALMA), currently one of the most powerful radio interferometers.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    It is jointly operated by the European Southern Observatory (ESO), by the National Radio Astronomy Observatory (NRAO), and by the National Astronomical Observatory of Japan (NAOJ). The astronomers observed the objects at a wavelength of 0.87 millimetres to trace dust and gas at an angular resolution of 0.1 arcseconds. This angle corresponds to the size of a human’s pupil at a distance of around 10 kilometres. Published data complement the investigation. While considering the optical response of the telescope, they modelled the likely correct shape of the disks.

    Half of the disks Kurtovic and his colleagues investigated show ring-like dust structures that extend between 50 and 90 times the distance between the Sun and Earth (defined as 1 astronomical unit = 1 au). Their arrangements appear similar to the ones of larger disks of more massive young stars like HL Tau, whose images continue to fascinate astronomers. They commonly explain such rings as giant planets accumulating dust and gas while orbiting the central star. “We explored several alternative physical processes to explain the patterns, such as stellar irradiation evaporating the dust. Still, planet interaction remains to be the most plausible explanation also for our VLMS sample”, Kurtovic says. The sizes of the gaps cleared by such planets around VLMS would require planetary masses similar to Saturn.

    The disks around VLMS indeed contain enough material to feed new-born planets. However, this is not the biggest challenge. Confining the dust quickly enough to build planetary embryos on which the gas accumulates to form planets is even more difficult. Time is of the essence because the dust gradually moves inward and eventually evaporates close to the star. This radial migration is about twice as fast as for the more massive stars, leaving little time for the rocky embryos to grow.

    2
    Observational data and model of the dust disk around the VLMS MHO6. Left: Image of the dust disk. Middle: The disk model with a 20 au wide central hole, which is consistent with a Saturn-mass planet located at a distance of 7 au from the star, accreting disk material. Right: Radial profile of the model (blue) and after convolving it with the telescope’s angular resolution (red). The black symbols represent the data obtained from the measured brightness distribution. The grey bar corresponds to the angular resolution of the observations. Credit: Kurtovic et al./MPIA.

    “We estimate that the ringed structures we see around the VLMS must have formed within only 200,000 years before the dust would have migrated to the central star”, Dr Paola Pinilla explains. Pinilla leads a research group at MPIA titled The Genesis of Planets in which Kurtovic is a member. Once these embryos are present, the gaps they carve while orbiting the star serve as a border that the dust cannot cross. At this stage, the planet can grow steadily by accreting gas and dust. Kurtovic and his colleagues demonstrate that the dust disks are embedded in gas disks four times the size. Initially, they both must have had the same size, which tells us how far the dust had migrated before taking up its current position.

    In the remaining three of the six disks observed, the dust appears more centrally concentrated to sizes between 20 and 40 au. They lack an apparent structure, which is probably the result of the inadequate angular resolution. “We think that we will see rings even inside the smaller disks once we obtain better-resolved observations”, Kurtovic predicts.

    “This pilot study was a challenging task because the VLMS disks are small and possess relatively little material, resulting in feeble signals that are very hard to detect,” Pinilla admits. However, the investigation has shown that, with the right instrumentation, astronomers can look into planets’ birthplaces even in the faint disks of VLMS. This ability opens a new door that supports the theorists’ efforts to develop an adequate model of planet formation for even the smallest stars, which live longer than any other type of star.

    “We still do not know how common planets around Red Dwarf stars are”, Kurtovic concedes. “However, the longevity of Red Dwarf planetary systems is intriguing concerning habitability and hypothetical civilisations”, he adds. In this sense, these faint red stars may be the most interesting ones in the Galaxy.

    Science paper:
    Size and structures of disks around very low mass stars in the Taurus star-forming region
    Astronomy & Astrophysics

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Max Planck Institute for Astronomy, Heidelburg, GE

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

     
  • richardmitnick 12:39 pm on January 20, 2021 Permalink | Reply
    Tags: "The dance of massive stellar couples", A relatively small proportion of the new stars have masses of more than eight times that of the Sun and are therefore considered massive., Astronomers find evidence for stars of young binary systems to approach one another within the first million years after birth., , , , Conservation of angular momentum, , Evidence now that massive stars form in wide orbits that shrink rapidly as both stars approach each other after birth., MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), Radial velocity, Spectrographs split light into its colour components which physicists call a spectrum., Stars usually form in clusters within clouds of gas and dust., The research group observed several young star formation regions., The researchers used various spectrographs mounted on the Very Large Telescope (VLT) of the European Southern Observatory (ESO) in the Chilean Atacama Desert., We do not yet know how binary star systems form.   

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE): “The dance of massive stellar couples” 

    Max Planck Institut für Astronomie (DE)

    From MPG Institute for Astronomy [MPG Institut für Astronomie] (DE)

    January 20, 2021

    Dr. Markus Nielbock
    Press and public relations officer
    Max Planck Institute for Astronomy, Heidelberg
    +49 6221 528-134
    pr@mpia.de
    MPIA

    Dr. María Claudia Ramírez-Tannus
    Max Planck Institute for Astronomy,
    Heidelberg +49 6221 528-228
    ramirez@mpia.de
    MPIA

    Astronomers find evidence for stars of young binary systems to approach one another within the first million years after birth.

    Most massive stars occur in close pairs in which both stars orbit the common centre of mass. However, we do not yet know how such binary star systems form. A group of astronomers led by María Claudia Ramírez-Tannus from the Max Planck Institute for Astronomy in Heidelberg, Germany, have now found evidence that massive stars form in wide orbits that shrink rapidly, and both stars approach each other after birth. The researchers inferred this from a shift in the velocity spread of the massive stars to larger values the older the star cluster becomes. They attribute this effect to a reduction in the stellar orbital radii of massive binaries.

    1
    Illustration of two scenarios that explain how the orbits of massive stars shrink over time. a) Both partners of a double star emerge from a disk of gas and dust. On their orbits through the more dilute residual disk, the friction causes the radii of their orbits to decrease, which leads to an increase in orbital velocities. b) In a triple system, a low-mass star orbits two higher-mass stars. The low-mass star’s gravitational influence forces the inner stars to follow elliptical orbits, which in time converge towards closer circular orbits. © MPIA graphics department.

    Stars usually form in clusters within clouds of gas and dust. A relatively small proportion of them have masses of more than eight times that of the Sun and are therefore considered massive. For still unknown reasons, they often form binary star systems with small separations between the individual stars. A group of astronomers led by María Claudia Ramírez-Tannus from the Max Planck Institute for Astronomy (MPIA) in Heidelberg have now discovered that the velocity dispersion of massive stars increases rapidly with the age of the clusters they belong to. The team attributes the effect to the increase in the orbital speeds of the massive binaries as the stars gradually converge and their orbits shrink.

    For ideal situations, this effect is known as the conservation of angular momentum. The law states that a rotation speed increases when mass moves to the centre of the circular motion. We see this, for example, during the pirouettes of figure skaters, who bring their arms to the body for faster rotation. Although stellar binaries do not fully comply with this law, the analogy is still correct in qualitative terms.

    In recent years, the research group have observed several young star formation regions. They measured the speed of individual massive stars and determined their luminosity and surface temperature. To do this, they used various spectrographs mounted on the Very Large Telescope (VLT) of the European Southern Observatory (ESO) in the Chilean Atacama Desert.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

    Like a prism, these instruments split light into its colour components, which physicists call a spectrum. The spectrographs capture the spectral lines of chemical elements in the stellar atmospheres and notice even the smallest wavelength shifts. Using this ability, the research team have now derived the speeds at which the stars move along the line of sight, the so-called radial velocity. They also supplemented their data set with previously published results. When the astronomers combined all these velocities, they obtained the massive stars’ velocity dispersion, a statistical measure of the spread of radial velocities.

    “Our results suggest that massive binary stars initially form on large orbits and within little time develop into close binary systems,” explains Ramírez-Tannus. “This is an important finding that helps to narrow down the models of formation mechanisms.” Indeed, massive double stars in older star clusters tend to have close orbits with orbital periods of between a few days and weeks.

    To understand what causes stars to move closer together, scientists propose two scenarios. Stars form from dense condensations within large clouds of gas and dust. During the star formation process, rotation causes this condensation to flatten into a disk, while the star emerges at the centre. If massive binary stars already form as pairs, their orbits pervade the residual disk. Friction with the disk material causes the orbits to shrink and the orbital speed increases.

    2
    Graphical representation of the results. Left: The velocity dispersions of massive stars in ten star formation regions compared to the star clusters’ age. The colours indicate different sources of the data. The black line shows the linear relationship, while the grey area indicates the uncertainty of the slope. Right: The lowest orbital periods of massive binary star systems compared to cluster age. The blue line corresponds to the mean trend. The light blue zone marks the area of uncertainty. © Image: Ramírez-Tannus et al./MPIA.

    The second mechanism occurs in systems with a third, lower-mass star. Its gravitational force diverts the more massive companions into elliptical orbits that over time approach smaller and circular trajectories. The reduced orbital radii again lead to higher velocities. In some cases, the lower-mass star is ejected from the system.

    The random movement of stars in a cluster results in a narrow range of speeds, which leads to a dispersion of only a few kilometres per second. However, if there are enough close massive binary stars in the cluster, their fast orbital speeds shift the dispersion to higher values.

    Measuring stellar luminosities and surface temperatures from the spectra establishes the connection to the age of the clusters. Depending on their mass, stars have a characteristic combination of luminosity and temperature, which changes with age. Hence, by measuring the stellar properties of the stars, astronomers can determine the age of clusters.

    By combining the results, the scientists around Ramírez-Tannus found a correlation between the velocity dispersion of massive stars in clusters and their age, suggesting that the dispersion increases rapidly within a few million years. The astronomers conclude that the orbital velocities of the binaries increase, which indicates the orbits becoming correspondingly smaller.

    However, the velocity dispersions only provide a restricted view of the processes that occur inside the individual binary systems. Therefore, co-author Frank Backs of the University of Amsterdam has employed simulations to extract information on the orbital periods of binary stars that are consistent with the measured velocity dispersions.

    “I simulated many clusters by varying the orbital period distribution of their binary systems. This way, I managed to compute which of them would result in the observed velocity dispersions,” Backs explains. He adds, “many simulations are required because we do not know the systems’ exact properties such as their orientation, which impact the observed dispersions.“

    Overall, the study has shown a clear trend in which the smallest orbital periods decrease from months to a few days within about 1.6 million years. “Despite the partially large uncertainties of the individual measurements, the trend is clear,” María Claudia Ramírez-Tannus notes. “Although the time scale determined is not yet very accurate, we can conclude that by astronomical standards, the orbits of massive binary stars shrink rapidly.”

    Science paper:
    The young stellar content of the giant H II regions M 8, G333.6−0.2, and NGC 6357 with VLT/KMOS
    Astronomy & Astrophysics

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Max Planck Institute for Astronomy, Heidelburg, GE

    The MPG Institute for Astronomy [MPG Institut für Astronomie] (DE), MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy.

    In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute’s own workshops.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: