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  • richardmitnick 8:56 am on July 4, 2020 Permalink | Reply
    Tags: , , , Exoplanets, , , TESS mission discovers massive ice giant", The exoplanet UCF-1.01, TOI-849 b is the most massive Neptune-sized planet discovered to date and the first to have a density that is comparable to Earth.   

    From MIT News: “TESS mission discovers massive ice giant” 

    MIT News

    From MIT News

    July 1, 2020
    Jennifer Chu

    1
    In our solar system, the “ice giants” Neptune and Uranus are far less dense than rocky Venus and Earth. But astrophysicists on NASA’s TESS mission have now found an exoplanet, TOI-849b, that appears to be 40 times more massive than Earth, yet just as dense. This illustration depicts the exoplanet, UCF-1.01. Like TOI-849b, this exoplanet also orbits close to a star and is like “hot Neptune.” Image credit: NASA/JPL-Caltech.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The “ice giant” planets Neptune and Uranus are much less dense than rocky, terrestrial planets such as Venus and Earth. Beyond our solar system, many other Neptune-sized planets, orbiting distant stars, appear to be similarly low in density.

    Now, a new planet discovered by NASA’s Transiting Exoplanet Survey Satellite, TESS, seems to buck this trend. The planet, named TOI-849 b, is the 749th “TESS Object of Interest” identified to date. Scientists spotted the planet circling a star about 750 light years away every 18 hours, and estimate it is about 3.5 times larger than Earth, making it a Neptune-sized planet. Surprisingly, this far-flung Neptune appears to be 40 times more massive than Earth and just as dense.

    TOI-849 b is the most massive Neptune-sized planet discovered to date, and the first to have a density that is comparable to Earth.

    “This new planet is more than twice as massive as our own Neptune, which is really unusual,” says Chelsea Huang, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team. “Imagine if you had a planet with Earth’s average density, built up to 40 times the Earth’s mass. It’s quite crazy to think what’s happening at the center of a planet with that kind of pressure.”

    The discovery is reported today in the journal Nature. The study’s authors include Huang and members of the TESS science team at MIT.

    A blasted Jupiter?

    Since its launch on April 18, 2018, the TESS satellite has been scanning the skies for planets beyond our solar system. The project is one of NASA’s Astrophysics Explorer missions and is led and operated by MIT. TESS is designed to survey almost the entire sky by pivoting its view every month to focus on a different patch of the sky as it orbits the Earth. As it scans the sky, TESS monitors the light from the brightest, nearest stars, and scientists look for periodic dips in starlight that may signal that a planet is crossing in front of a star.

    Data taken by TESS, in the form of a star’s light curve, or measurements of brightness, is first made available to the TESS science team, an international, multi-institute group of researchers led by scientists at MIT. These researchers get a first look at the data to identify promising planet candidates, or TESS Objects of Interest. These are shared publicly with the general scientific community along with the TESS data for further analysis.

    For the most part, astronomers focus their search for planets on the nearest, brightest stars that TESS has observed. Huang and her team at MIT, however, recently had some extra time to look over data during September and October of 2018, and wondered if anything could be found among the fainter stars. Sure enough, they discovered a significant number of transit-like dips from a star 750 light years away, and soon after, confirmed the existence of TOI-849 b.

    “Stars like this usually don’t get looked at carefully by our team, so this discovery was a happy coincidence,” Huang says.

    Follow-up observations of the faint star with a number of ground-based telescopes further confirmed the planet and also helped to determine its mass and density.

    Huang says that TOI-849 b’s curious proportions are challenging existing theories of planetary formation.

    “We’re really puzzled about how this planet formed,” Huang says. “All the current theories don’t fully explain why it’s so massive at its current location. We don’t expect planets to grow to 40 Earth masses and then just stop there. Instead, it should just keep growing, and end up being a gas giant, like a hot Jupiter, at several hundreds of Earth masses.”

    One hypothesis scientists have come up with to explain the new planet’s mass and density is that perhaps it was once a much larger gas giant, similar to Jupiter and Saturn — planets with more massive envelopes of gas that enshroud cores thought to be as dense as the Earth.

    As the TESS team proposes in the new study, over time, much of the planet’s gassy envelope may have been blasted away by the star’s radiation — not an unlikely scenario, as TOI-849 b orbits extremely close to its host star. Its orbital period is just 0.765 days, or just over 18 hours, which exposes the planet to about 2,000 times the solar radiation that Earth receives from the sun. According to this model, the Neptune-sized planet that TESS discovered may be the remnant core of a much more massive, Jupiter-sized giant.

    “If this scenario is true, TOI-849 b is the only remnant planet core, and the largest gas giant core known to exist,” says Huang. “This is something that gets scientists really excited, because previous theories can’t explain this planet.”

    This research was funded, in part, by NASA.

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 3:58 pm on June 16, 2020 Permalink | Reply
    Tags: "As many as six billion Earth-like planets in our galaxy according to new estimates", , , , , Exoplanets, Kepler data continues to deliver.,   

    From University of British Columbia: “As many as six billion Earth-like planets in our galaxy, according to new estimates” 

    U British Columbia bloc

    From University of British Columbia

    via


    From phys.org

    June 16, 2020

    To be considered Earth-like, a planet must be rocky, roughly Earth-sized and orbiting Sun-like (G-type) stars. It also has to orbit in the habitable zones of its star—the range of distances from a star in which a rocky planet could host liquid water, and potentially life, on its surface.

    1
    Artist’s conception of Kepler telescope observing planets transiting a distant star. Credit: NASA Ames/W Stenzel.

    “My calculations place an upper limit of 0.18 Earth-like planets per G-type star,” says UBC researcher Michelle Kunimoto, co-author of the new study in The Astronomical Journal. “Estimating how common different kinds of planets are around different stars can provide important constraints on planet formation and evolution theories, and help optimize future missions dedicated to finding exoplanets.”

    According to UBC astronomer Jaymie Matthews: “Our Milky Way has as many as 400 billion stars, with seven percent of them being G-type. That means less than six billion stars may have Earth-like planets in our Galaxy.”

    Previous estimates of the frequency of Earth-like planets range from roughly 0.02 potentially habitable planets per Sun-like star, to more than one per Sun-like star.

    Typically, planets like Earth are more likely to be missed by a planet search than other types, as they are so small and orbit so far from their stars. That means that a planet catalog represents only a small subset of the planets that are actually in orbit around the stars searched. Kunimoto used a technique known as ‘forward modeling’ to overcome these challenges.

    “I started by simulating the full population of exoplanets around the stars Kepler searched,” she explained. “I marked each planet as ‘detected’ or ‘missed’ depending on how likely it was my planet search algorithm would have found them. Then, I compared the detected planets to my actual catalog of planets. If the simulation produced a close match, then the initial population was likely a good representation of the actual population of planets orbiting those stars.”

    Kunimoto’s research also shed more light on one of the most outstanding questions in exoplanet science today: the ‘radius gap’ of planets. The radius gap demonstrates that it is uncommon for planets with orbital periods less than 100 days to have a size between 1.5 and two times that of Earth. She found that the radius gap exists over a much narrower range of orbital periods than previously thought. Her observational results can provide constraints on planet evolution models that explain the radius gap’s characteristics.

    Previously, Kunimoto searched archival data from 200,000 stars of NASA’s Kepler mission. She discovered 17 new planets outside of the Solar System, or exoplanets, in addition to recovering thousands of already known planets.

    See the full article here .

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    U British Columbia Campus

    The University of British Columbiais a global centre for research and teaching, consistently ranked among the 40 best universities in the world. Since 1915, UBC’s West Coast spirit has embraced innovation and challenged the status quo. Its entrepreneurial perspective encourages students, staff and faculty to challenge convention, lead discovery and explore new ways of learning. At UBC, bold thinking is given a place to develop into ideas that can change the world.

     
  • richardmitnick 11:15 am on May 28, 2020 Permalink | Reply
    Tags: , , , , , Exoplanets, Possible disintegrating planet in the nearby planetary system DMPP-1.   

    From AAS NOVA: ” Are We Watching a Planet Disintegrate?” 

    AASNOVA

    From AAS NOVA

    27 May 2020
    Susanna Kohler

    1
    Artist’s illustration of the possible disintegrating planet in the nearby planetary system DMPP-1. [Mark A. Garlick/Haswell/ Barnes/Staab/Open University]

    Among the wealth of exoplanets we’ve discovered beyond our solar system, some are temperate, some less so. New observations have now revealed what may be a particularly inhospitable environment: a planet literally disintegrating as it orbits its host.

    2
    Artist’s illustration of another DMPP-discovered planetary system, DMPP-2. [Mark A. Garlick/Haswell/ Barnes/Staab/Open University]

    Peering Through the Shroud

    With initial observations in 2015, the Dispersed Matter Planet Project (DMPP) promised an innovative approach to hunting for exoplanets closely orbiting their hosts. Using high-cadence, high-precision radial velocity measurements, the project targets bright nearby stars that shows signatures of being shrouded in hot circumstellar gas. By looking for tiny radial-velocity wiggles in the star’s signal, the DMPP team hopes to detect small planets that are losing mass as they orbit close to their hot hosts.

    Radial Velocity Method-Las Cumbres Observatory

    In December 2019, DMPP announced its first discoveries: six planets orbiting around three different target stars. Now, in a new publication led by scientist Mark Jones (The Open University, UK), the team has revisited the first of these systems, DMPP-1, with follow-up photometry from the Transiting Exoplanet Survey Satellite (TESS).

    NASA/MIT TESS replaced Kepler in search for exoplanets

    Intriguingly, the radial-velocity-detected planets are not the only signals from this system.

    Missing the Expected, but Finding the Unexpected

    DMPP-1 is a 2-billion-year-old star located just over 200 light-years away. The radial-velocity observations of this system revealed the gravitational tugs of four planets all orbiting with periods of less than 19 days. The radial-velocity data suggest that this system is probably near edge-on and contains three super-Earths and one Neptune-like planet.

    Jones and collaborators began their photometric follow-up by searching TESS data for evidence of these four planets transiting across the host star’s face. Interestingly, they found no sign of transits at the predicted periods — indicating that the four radial-velocity planets are either smaller than expected, or that the system isn’t quite edge-on after all, so the planets don’t pass directly in front of the star.

    The authors did, however, find a new signal: a weak transit detection with a period of just ~3.3 days. This signal doesn’t match any of the known radial-velocity planets.

    A Disappearing Planet?

    What might this marginal detection be? Its variable transit depths, short period, and apparent small size are all consistent with a catastrophically disintegrating exoplanet — a close-in, small, rocky planet that is so irradiated by its host that its rocky surface is being sublimated. As time goes on, such a planet will eventually disintegrate into nothing.

    This transit signal still needs to be confirmed with additional follow-up photometric observations. Assuming it proves to be a true detection, however, such a disintegrating, rocky planet orbiting a bright nearby star would provide a veritable gold mine of information.

    By exploring the transit signals from DMPP-1 with future technology like the James Webb Space Telescope, we will be able to examine the composition of the ablated material, potentially revealing clues as to how hot, rocky inner planets form and evolve.

    Citation

    “A Possible Transit of a Disintegrating Exoplanet in the Nearby Multiplanet System DMPP-1,” Mark H. Jones et al 2020 ApJL 895 L17.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab8f2b

    See the full article here .


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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 1:28 pm on May 15, 2020 Permalink | Reply
    Tags: , , , Carole Haswell, , , , Exoplanets   

    From ESOblog: “Hunting hot exoplanets” 

    ESO 50 Large

    From ESOblog

    15 May 2020
    Science Snapshots

    1
    Carole Haswell

    In December 2019, astronomers announced that they had efficiently discovered and characterised planets outside the Solar System using an innovative technique. So far, the researchers have used the technique with ESO’s HARPS instrument to find six exoplanets, some of which hold the key to unlocking the geology of rocky planets. We spoke to lead researcher Carole Haswell from the Open University in the UK to find out more about the project and the implications of these discoveries.

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    2
    Artist’s impression of the mass-losing giant planet DMPP-2b, which orbits the pulsating star DMPP-2 every five days. The star is viewed through a cloud of gas lost from the hot planet.
    Credit: Mark A. Garlick / markgarlick.com. Science credit: Haswell / Barnes / Staab

    Q. The Dispersed Matter Planet Project (DMPP) aims to find lots of new exoplanets. What motivated you to start this project?

    A. The project actually grew out of some research we did a decade ago using the Hubble Space Telescope. We were looking at giant exoplanets, and found that the chromosphere of one of the host stars was missing. It seemed extremely unlikely that this star would be structured differently to every other star we know of, so we had another idea: when planets orbit close to their host star, they are heated very vigorously which makes them lose mass. We figured that some of this mass could form a gas shroud that envelops the entire planetary system and absorbs the light from the star’s chromosphere, preventing us from seeing it.

    So, we had the idea that if we see a star with missing chromospheric emission, we know that there is a hot mass-losing planet present, and could actually deduce a lot of information about such a planet. In this way, we came up with a new and efficient technique to discover new low-mass planets orbiting close to their parent star.

    What makes the project really special is our target star selection. Astronomers are beginning to suspect that most stars have planets orbiting them, but when we know what kind of planet a star might host, we can tailor the observations to find out about the planet much more quickly. And this is exactly what we’ve been doing here.

    Q. Could you tell us a bit about how this new planet-searching technique works?

    A. We searched through existing data on 6000 stars to find any that were structured like the Sun but with missing emission from their chromospheres. Of these 6000, we found about 40 that we thought could host very hot mass-losing planets. As these were all nearby stars, we guessed that these planets would have been found already if they were large and massive, so we thought they must be small, light planets. Therefore we designed observations to find them using the very sensitive HARPS instrument on the ESO 3.6-metre telescope [below and above].

    Because we were expecting low-mass planets orbiting close to their host stars — and therefore orbiting very quickly — we needed to get frequent measurements of the same star to see the differences during the planet’s orbit. So we looked at each star several times a night, which is much more often than observations are usually designed.

    Visiting La Silla Observatory to use the ESO 3.6-metre telescope was one of the most amazing experiences of my life. I’d used the New Technology Telescope [below] some years ago, but because I believe that this research is the best idea I’ve had in my whole career, it was especially exciting to go this time round.

    Q. What makes HARPS so good at finding new planetary systems?

    A. For this project, we are using the radial velocity method to detect planets, which means we measure how quickly the star moves towards and away from us. When a planet orbits a star, it pulls the star towards itself slightly. This means that when the planet orbits the star, the star is also executing a much smaller orbit in response. The star moves towards us while the planet moves away from us and vice versa. We can detect these changes in the star’s velocity from Earth.


    The radial velocity method for finding exoplanets. Credit: ESO/L. Calçada.

    We chose to use HARPS because it is by far the best general user radial velocity instrument that we were allowed to propose for — it can measure the velocity of a star with a precision of less than one metre per second! It’s fantastic to be in an ESO Member State with the opportunity to use such an instrument.

    Q. So why do you think it is important for us to search for new exoplanets?

    A. One of the biggest human questions is about our place in the Universe; how special the Solar System is and how special Earth is. And one of the big pushes in exoplanet science is to extend discovery methods to be able to see planets like Earth orbiting their host stars at the same distance that Earth orbits the Sun. The idea is that these Earth-like planets could be good candidates for hosting life.

    But it’s also important to find a whole range of planetary systems to see how planets form and evolve and to determine how typical the Solar System is. The planets we are studying through this project aren’t similar to our neighbours in the Solar System, but it is nonetheless important to study them because it gives us the opportunity to better understand a different type of planet, which is important to generally understand the geology and geochemistry of planetary systems.

    With further study of the systems we’ve found to host exoplanets, we could work out the chemical composition of the gas shroud, which would reveal what type of rock the surfaces of these planets are made of. This will help us pin down how planets are built, and whether the Earth is normal.

    Q. How has the DMPP been going so far? Have you had any surprising discoveries?

    A. We started making observations in 2015, and we’ve already discovered six exoplanets using relatively little telescope time compared to more traditional methods. One of the most interesting stars we looked at so far actually turned out to be two stars! The tiny second star in the binary system is right at the lower limit of hydrogen burning, meaning it is just massive enough to be a proper star like the Sun. If it had slightly less material, it would be a brown dwarf. This star is faint and had therefore never been detected before. Finding this extremely low mass star was interesting in its own right, but we also found a planet in this system that is 2–3 times the mass of Earth and orbits the larger star in just seven days, which is unusually quick. The planet doesn’t fit with our theories of planet formation because the smaller star’s presence means there wouldn’t have been enough rocky material to form the planet where we see it. The second star must have affected the planet’s orbit, somehow pushing it closer to the larger star.

    We would really like to study this system in more detail; if we can get more radial velocity data, we could see if there are any other planets, pin down the properties of the planet we’ve already discovered, and look at the atmosphere of the smaller star to see how it changes as it gets close to the larger star.

    Q. Are there any challenges that you’ve had to overcome?

    A. For many of our target stars we have detected more than one orbiting planet, so it took us a while to disentangle the signals from each other to figure out the exact number of planets and their orbital periods. This meant it was longer than expected before we could publish our results, so the committee that allocates telescope time started becoming sceptical and we had to persuade them that our research really is worthwhile. We’ve now published several papers on our discoveries, and we were allocated more time to continue the project — both to look at more systems and to investigate the most interesting ones in more detail. Unfortunately these observations couldn’t take place because of the closure of the observatory due to COVID-19, but we are really keen to continue as soon as it is safe to do so!

    See the full article here .


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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    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,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

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

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 8:39 am on April 30, 2020 Permalink | Reply
    Tags: , , , , , , Exoplanets   

    From Arizona State University: “ASU scientists lead study of galaxy’s ‘water worlds'” 


    From Arizona State University

    April 20, 2020
    Karin Valentine

    1

    Astrophysical observations have shown that Neptune-like water-rich exoplanets are common in our galaxy. These “water worlds” are believed to be covered with a thick layer of water, hundreds to thousands of miles deep, above a rocky mantle.

    While water-rich exoplanets are common, their composition is very different from Earth, so there are many unknowns in terms of these planets’ structure, composition and geochemical cycles.

    In seeking to learn more about these planets, an international team of researchers, led by Arizona State University, has provided one of the first mineralogy lab studies for water-rich exoplanets. The results of their study have been recently published in the journal Proceedings of the National Academy of Sciences.

    “Studying the chemical reactions and processes is an essential step toward developing an understanding of these common planet types,” said co-author Dan Shim, of ASU’s School of Earth and Space Exploration.

    The general scientific conjecture is that water and rock form separate layers in the interiors of water worlds. Because water is lighter, underneath the water layer in water-rich planets, there should be a rocky layer. However, the extreme pressure and temperature at the boundary between water and rocky layers could fundamentally change the behaviors of these materials.

    To simulate this high pressure and temperature in the lab, lead author and research scientist Carole Nisr conducted experiments at Shim’s Lab for Earth and Planetary Materials at ASU using high pressure diamond-anvil cells.

    For their experiment, the team immersed silica in water, compressed the sample between diamonds to a very high pressure, then heated the sample with laser beams to over a few thousand degrees Fahrenheit.

    The team also conducted laser heating at the Argonne National Laboratory in Illinois. To monitor the reaction between silica and water, X-ray measurements were taken while the laser heated the sample at high pressures.

    What they found was an unexpected new solid phase with silicon, hydrogen and oxygen all together.

    “Originally, it was thought that water and rock layers in water-rich planets were well-separated,” Nisr said. “But we discovered through our experiments a previously unknown reaction between water and silica and stability of a solid phase roughly in an intermediate composition. The distinction between water and rock appeared to be surprisingly ‘fuzzy’ at high pressure and high temperature.”

    The researchers hope that these findings will advance our knowledge on the structure and composition of water-rich planets and their geochemical cycles.

    “Our study has important implications and raises new questions for the chemical composition and structure of the interiors of water-rich exoplanets,” Nisr said. “The geochemical cycle for water-rich planets could be very different from that of the rocky planets, such as Earth.”

    In addition to Nisr and Shim, co-authors from ASU include alumni Huawei Chen; Kurt Leinenweber of ASU’s Eyring Materials Center; and Andrew Chizmeshya of ASU’s School of Molecular Sciences. Additional researchers on the team represent the University of Chicago, University of Cologne (Germany), Argonne National Laboratory (Illinois) and George Washington University (Washington, D.C.).

    See the full article here .


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    ASU is the largest public university by enrollment in the United States. Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College. A 1958 statewide ballot measure gave the university its present name.
    ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded patents and awarded research grant proposals. The Center for Measuring University Performance currently ranks ASU 31st among top U.S. public research universities.

    ASU awards bachelor’s, master’s and doctoral degrees in 16 colleges and schools on five locations: the original Tempe campus, the West campus in northwest Phoenix, the Polytechnic campus in eastern Mesa, the Downtown Phoenix campus and the Colleges at Lake Havasu City. ASU’s “Online campus” offers 41 undergraduate degrees, 37 graduate degrees and 14 graduate or undergraduate certificates, earning ASU a Top 10 rating for Best Online Programs. ASU also offers international academic program partnerships in Mexico, Europe and China. ASU is accredited as a single institution by The Higher Learning Commission.

     
  • richardmitnick 9:58 am on April 29, 2020 Permalink | Reply
    Tags: , , , , Exoplanets, , Kepler-88 d - a planet three times the mass of Jupiter in a distant planetary system.   

    From Keck Observatory: “Newly Discovered Exoplanet Dethrones Former King of Kepler-88 Planetary System” 

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    From Keck Observatory

    Hawaii Astronomer Discovers Massive Extrasolar Planet with Maunakea Telescope.

    Our solar system has a king. The planet Jupiter, named for the most powerful god in the Greek pantheon, has bossed around the other planets through its gravitational influence. With twice the mass of Saturn, and 300 times that of Earth, Jupiter’s slightest movement is felt by all the other planets. Jupiter is thought to be responsible for the small size of Mars, the presence of the asteroid belt, and a cascade of comets that delivered water to young Earth.

    Do other planetary systems have gravitational gods like Jupiter?

    A team of astronomers led by the University of Hawaiʻi Institute for Astronomy (UH IfA) has discovered a planet three times the mass of Jupiter in a distant planetary system.

    The discovery is based on six years of data taken at W. M. Keck Observatory on Maunakea in Hawaiʻi. Using the High-Resolution Echelle Spectrometer (HIRES) instrument on the 10-meter Keck I telescope, the team confirmed that the planet, named Kepler-88 d, orbits its star every four years, and its orbit is not circular, but elliptical.

    Keck Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope, Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level

    At three times the mass of Jupiter, Kepler-88 d is the most massive planet in this system.

    The system, Kepler-88, was already famous among astronomers for two planets that orbit much closer to the star, Kepler-88 b and c (planets are typically named alphabetically in the order of their discovery).

    Those two planets have a bizarre and striking dynamic called mean motion resonance. The sub-Neptune sized planet b orbits the star in just 11 days, which is almost exactly half the 22-day orbital period of planet c, a Jupiter-mass planet. The clockwork-like nature of their orbits is energetically efficient, like a parent pushing a child on a swing. Every two laps planet b makes around the star, it gets pumped. The outer planet, Kepler-88 c, is twenty times more massive than planet b, and so its force results in dramatic changes in the orbital timing of the inner planet.

    Kepler-88 Planetary System from Keck Observatory on Vimeo.
    Kepler-88 d has three times the mass of Kepler-88 c, making the newly found planet the most massive one known in this system. ANIMATION CREDIT: W. M. KECK OBSERVATORY/ADAM MAKARENKO

    Astronomers observed these changes, called transit timing variations, with the NASA Kepler space telescope, which detected the precise times when Kepler-88 b crossed (or transited) between the star and the telescope. Although transit timing variations (TTVs for short) have been detected in a few dozen planetary systems, Kepler-88 b has some of the largest timing variations. With transits arriving up to half a day early or late, the system is known as “the King of TTVs.”

    The newly discovered planet adds another dimension to astronomers’ understanding of the system.

    “At three times the mass of Jupiter, Kepler-88 d has likely been even more influential in the history of the Kepler-88 system than the so-called King, Kepler-88 c, which is only one Jupiter mass,” says Dr. Lauren Weiss, Beatrice Watson Parrent Postdoctoral Fellow at UH IfA and lead author on the discovery team. “So maybe Kepler-88 d is the new supreme monarch of this planetary empire – the empress.”

    Perhaps these extrasolar sovereign leaders have had as much influence as Jupiter did for our solar system. Such planets might have promoted the development of rocky planets and directed water-bearing comets toward them. Dr. Weiss and colleagues are searching for similar royal planets in other planetary systems with small planets.

    Their paper announcing the discovery of Kepler-88 d is published in today’s issue of The Astronomical Journal.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

     
  • richardmitnick 11:34 am on January 3, 2020 Permalink | Reply
    Tags: "Alien life is out there, , , , Biological signatures, but our theories are probably steering us away from it", , Exoplanets, ,   

    From phys.org: “Alien life is out there, but our theories are probably steering us away from it” 


    From phys.org

    January 3, 2020
    Peter Vickers

    1
    Credit: sdecoret/Shutterstock

    If we discovered evidence of alien life, would we even realize it? Life on other planets could be so different from what we’re used to that we might not recognize any biological signatures that it produces.

    Recent years have seen changes to our theories about what counts as a biosignature and which planets might be habitable, and further turnarounds are inevitable. But the best we can really do is interpret the data we have with our current best theory, not with some future idea we haven’t had yet.

    This is a big issue for those involved in the search for extraterrestrial life. As Scott Gaudi of Nasa’s Advisory Council has said: “One thing I am quite sure of, now having spent more than 20 years in this field of exoplanets … expect the unexpected.”

    But is it really possible to “expect the unexpected”? Plenty of breakthroughs happen by accident, from the discovery of penicillin to the discovery of the cosmic microwave background radiation left over from the Big Bang. These often reflect a degree of luck on behalf of the researchers involved. When it comes to alien life, is it enough for scientists to assume “we’ll know it when we see it”?

    Many results seem to tell us that expecting the unexpected is extraordinarily difficult. “We often miss what we don’t expect to see,” according to cognitive psychologist Daniel Simons, famous for his work on inattentional blindness. His experiments have shown how people can miss a gorilla banging its chest in front of their eyes. Similar experiments also show how blind we are to non-standard playing cards such as a black four of hearts. In the former case, we miss the gorilla if our attention is sufficiently occupied. In the latter, we miss the anomaly because we have strong prior expectations.

    There are also plenty of relevant examples in the history of science. Philosophers describe this sort of phenomenon as “theory-ladenness of observation”. What we notice depends, quite heavily sometimes, on our theories, concepts, background beliefs and prior expectations. Even more commonly, what we take to be significant can be biased in this way.

    For example, when scientists first found evidence of low amounts of ozone in the atmosphere above Antarctica, they initially dismissed it as bad data. With no prior theoretical reason to expect a hole, the scientists ruled it out in advance. Thankfully, they were minded to double check, and the discovery was made.

    Could a similar thing happen in the search for extraterrestrial life? Scientists studying planets in other solar systems (exoplanets) are overwhelmed by the abundance of possible observation targets competing for their attention. In the last 10 years scientists have identified more than 3,650 planets—more than one a day. And with missions such as NASA’s TESS exoplanet hunter this trend will continue.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    Each and every new exoplanet is rich in physical and chemical complexity. It is all too easy to imagine a case where scientists do not double check a target that is flagged as “lacking significance,” but whose great significance would be recognized on closer analysis or with a non-standard theoretical approach.

    2
    More than 200,000 stars captured in one small section of the sky by Nasa’s TESS mission. Credit: NASA

    However, we shouldn’t exaggerate the theory-ladenness of observation. In the Müller-Lyer illusion, a line ending in arrowheads pointing outwards appears shorter than an equally long line with arrowheads pointing inwards. Yet even when we know for sure that the two lines are the same length, our perception is unaffected and the illusion remains. Similarly, a sharp-eyed scientist might notice something in her data that her theory tells her she should not be seeing. And if just one scientist sees something important, pretty soon every scientist in the field will know about it.

    History also shows that scientists are able to notice surprising phenomena, even biased scientists who have a pet theory that doesn’t fit the phenomena. The 19th-century physicist David Brewster incorrectly believed that light is made up of particles traveling in a straight line. But this didn’t affect his observations of numerous phenomena related to light, such as what’s known as birefringence in bodies under stress. Sometimes observation is definitely not theory-laden, at least not in a way that seriously affects scientific discovery.

    We need to be open-minded

    Certainly, scientists can’t proceed by just observing. Scientific observation needs to be directed somehow. But at the same time, if we are to “expect the unexpected,” we can’t allow theory to heavily influence what we observe, and what counts as significant. We need to remain open-minded, encouraging exploration of the phenomena in the style of Brewster and similar scholars of the past.

    3
    The Müller-Lyer optical illusion. Credit: Fibonacci/Wikipedia, CC BY-SA

    Studying the universe largely unshackled from theory is not only a legitimate scientific endeavor—it’s a crucial one. The tendency to describe exploratory science disparagingly as “fishing expeditions” is likely to harm scientific progress. Under-explored areas need exploring, and we can’t know in advance what we will find.

    In the search for extraterrestrial life, scientists must be thoroughly open-minded. And this means a certain amount of encouragement for non-mainstream ideas and techniques. Examples from past science (including very recent ones) show that non-mainstream ideas can sometimes be strongly held back. Space agencies such as NASA must learn from such cases if they truly believe that, in the search for alien life, we should “expect the unexpected.”

    See the full article here .

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    Please help promote STEM in your local schools.

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    About Phys.org in 100 Words

    Phys.org™ is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 12:02 pm on December 31, 2019 Permalink | Reply
    Tags: , , , , , ESA’s Characterising Exoplanet Satellite Cheops, Exoplanets, Future giant ground based optical telescopes, ,   

    From ars technica: “The 2010s: Decade of the exoplanet” 

    Ars Technica
    From ars technica

    12/31/2019
    John Timmer

    1
    Artist conception of Kepler-186f, the first Earth-size exoplanet found in a star’s “habitable zone.”

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The last ten years will arguably be seen as the “decade of the exoplanet.” That might seem like an obvious thing to say, given that the discovery of the first exoplanet was honored with a Nobel Prize this year. But that discovery happened back in 1995—so what made the 2010s so pivotal?

    One key event: 2009’s launch of the Kepler planet-hunting probe.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    Kepler spawned a completely new scientific discipline, one that has moved from basic discovery—there are exoplanets!—to inferring exoplanetary composition, figuring out exoplanetary atmosphere, and pondering what exoplanets might tell us about prospects for life outside our Solar System.

    To get a sense of how this happened, we talked to someone who was in the field when the decade started: Andrew Szentgyorgyi, currently at the Harvard-Smithsonian Center for Astrophysics, where he’s the principal investigator on the Giant Magellan Telescope’s Large Earth Finder instrument.

    Giant Magellan Telescope, 21 meters, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

    In addition to being famous for having taught your author his “intro to physics” course, Szentgyorgyi was working on a similar instrument when the first exoplanet was discovered.

    Two ways to find a planet

    The Nobel-winning discovery of 51 Pegasi b came via the “radial velocity” method, which relies on the fact that a planet exerts a gravitational influence on its host star, causing the star to accelerate slightly toward the planet.

    Radial Velocity Method-Las Cumbres Observatory

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

    Unless the planet’s orbit is oriented so that it’s perpendicular to the line of sight between Earth and the star, some of that acceleration will draw the star either closer to or farther from Earth. This acceleration can be detected via a blue or red shift in the star’s light, respectively.

    The surfaces of stars can expand and contract, which also produces red and blue shifts, but these won’t have the regularity of acceleration produced by an orbital body. But it explains why, back in the 1990s, people studying the surface changes in stars were already building the necessary hardware to study radial velocity.

    “We had a group that was building instruments that I’ve worked with to study the pulsations of stars—astroseismology,” Szentgyorgyi told Ars, “but that turns out to be sort of the same instrumentation you would use” to discern exoplanets.

    He called the discovery of 51 Pegasi b a “seismic event” and said that he and his collaborators began thinking about how to use their instruments “probably when I got the copy of Nature” that the discovery was published in. Because some researchers already had the right equipment, a steady if small flow of exoplanet announcements followed.

    During this time, researchers developed an alternate way to find exoplanets, termed the “transit method.”

    Planet transit. NASA/Ames

    The transit method requires a more limited geometry from an exoplanet’s orbit: the plane has to cause the exoplanet to pass through the line of sight between its host star and Earth. During these transits, the planet will eclipse a small fraction of light from the host star, causing a dip in its brightness. This doesn’t require the specialized equipment needed for radial velocity detections, but it does require a telescope that can detect small brightness differences despite the flicker caused by the light passing through our atmosphere.

    By 2009, transit detections were adding regularly to the growing list of exoplanets.

    The tsunami

    In the first year it was launched, Kepler started finding new planets. Given time and a better understanding of how to use the instrument, the early years of the 2010s saw thousands of new planets cataloged. In 2009, Szentgyorgyi said, “it was still ‘you’re finding handfuls of exoplanetary systems.’ And then with the launch of Kepler, there’s this tsunami of results which has transformed the field.”

    Suddenly, rather than dozens of exoplanets, we knew about thousands.

    2
    The tsunami of Kepler planet discoveries.

    The sheer numbers involved had a profound effect on our understanding of planet formation. Rather than simply having a single example to test our models against—our own Solar System—we suddenly had many systems to examine (containing over 4,000 currently known exoplanets). These include objects that don’t exist in our Solar System, things like hot Jupiters, super-Earths, warm Neptunes, and more. “You found all these crazy things that, you know, don’t make any sense from the context of what we knew about the Solar System,” Szentgyorgyi told Ars.

    It’s one thing to have models of planet formation that say some of these planets can form; it’s quite another to know that hundreds of them actually exist. And, in the case of hot Jupiters, it suggests that many exosolar systems are dynamic, shuffling planets to places where they can’t form and, in some cases, can’t survive indefinitely.

    But Kepler gave us more than new exoplanets; it provided a different kind of data. Radial velocity measurements only tell you how much the star is moving, but that motion could be caused by a relatively small planet with an orbital plane aligned with the line of sight from Earth. Or it could be caused by a massive planet with an orbit that’s highly inclined from that line of sight. Physics dictates that, from our perspective, these will produce the same acceleration of the star. Kepler helped us sort out the differences.

    3
    A massive planet orbiting at a steep angle (left) and a small one orbiting at a shallow one will both produce the same motion of a star relative to Earth.

    “Kepler not only found thousands and thousands of exoplanets, but it found them where we know the geometry,” Szentgyorgyi told Ars. “If you know the geometry—if you know the planet transits—you know your orbital inclination is in the plane you’re looking.” This allows follow-on observations using radial velocity to provide a more definitive mass of the exoplanet. Kepler also gave us the radius of each exoplanet.

    “Once you know the mass and radius, you can infer the density,” Szentgyorgyi said. “There’s a remarkable amount of science you can do with that. It doesn’t seem like a lot, but it’s really huge.”

    Density can tell us if a planet is rocky or watery—or whether it’s likely to have a large atmosphere or a small one. Sometimes, it can be tough to tell two possibilities apart; density consistent with a watery world could also be provided by a rocky core and a large atmosphere. But some combinations are either physically implausible or not consistent with planetary formation models, so knowing the density gives us good insight into the planetary type.

    Beyond Kepler

    Despite NASA’s heroic efforts, which kept Kepler going even after its hardware started to fail, its tsunami of discoveries slowed considerably before the decade was over. By that point, however, it had more than done its job. We had a new catalog of thousands of confirmed exoplanets, along with a new picture of our galaxy.

    For instance, binary star systems are common in the Milky Way; we now know that their complicated gravitational environment isn’t a barrier to planet formation.

    We also know that the most common type of star is the low-mass red dwarf. It was previously possible to think that the star’s low mass would be matched by a low-mass planet-forming disk, preventing the generation of large planets and the generation of large families of smaller planets. Neither turned out to be true.

    “We’ve moved into a mode where we can actually say interesting, global, statistical things about exoplanets,” Szentgyorgyi told Ars. “Most exoplanets are small—they’re sort of Earth to sub-Neptune size. It would seem that probably most of the solar-type stars have exoplanets.” And, perhaps most important, there’s a lot of them. “The ubiquity of exoplanets certainly is a stunner… they’re just everywhere,” Szentgyorgyi added.

    That ubiquity has provided the field with two things. First, it has given scientists the confidence to build new equipment, knowing that there are going to be planets to study. The most prominent piece of gear is NASA’s Transiting Exoplanet Survey Satellite, a space-based telescope designed to perform an all-sky exoplanet survey using methods similar to Kepler’s.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    But other projects are smaller, focused on finding exoplanets closer to Earth. If exoplanets are everywhere, they’re also likely to be orbiting stars that are close enough so we can do detailed studies, including characterizing their atmospheres. One famous success in this area came courtesy of the TRAPPIST telescopes [above], which spotted a system hosting at least seven planets. More data should be coming soon, too; on December 17, the European Space Agency launched the first satellite dedicated to studying known exoplanets.

    ESA/CHEOPS

    With future telescopes and associated hardware similar to what Szentgyorgyi is working on, we should be able to characterize the atmospheres of planets out to about 30 light years from Earth. One catch: this method requires that the planet passes in front of its host star from Earth’s point of view.

    When an exoplanet transits in front of its star, most of the light that reaches Earth comes directly to us from the star. But a small percentage passes through the atmosphere of the exoplanet, allowing it to interact with the gases there. The molecules that make up the atmosphere can absorb light of specific wavelengths—essentially causing them to drop out of the light that makes its way to Earth. Thus, the spectrum of the light that we can see using a telescope can contain the signatures of various gases in the exoplanet’s atmosphere.

    There are some important caveats to this method, though. Since the fraction of light that passes through the exoplanet atmosphere is small compared to that which comes directly to us from the star, we have to image multiple transits for the signal to stand out. And the host star has to have a steady output at the wavelengths we’re examining in order to keep its own variability from swamping the exoplanetary signal. Finally, gases in the exoplanet’s atmosphere are constantly in motion, which can make their signals challenging to interpret. (Clouds can also complicate matters.) Still, the approach has been used successfully on a number of exoplanets now.

    In the air

    Understanding atmospheric composition can tell us critical things about an exoplanet. Much of the news about exoplanet discoveries has been driven by what’s called the “habitable zone.” That zone is defined as the orbital region around a star where the amount of light reaching a planet’s surface is sufficient to keep water liquid. Get too close to the star and there’s enough energy reaching the planet to vaporize the water; get too far away and the energy is insufficient to keep water liquid.

    These limits, however, assume an atmosphere that’s effectively transparent at all wavelengths. As we’ve seen in the Solar System, greenhouse gases can play an outsized role in altering the properties of planets like Venus, Earth, and Mars. At the right distance from a star, greenhouse gases can make the difference between a frozen rock and a Venus-like oven. The presence of clouds can also alter a planet’s temperature and can sometimes be identified by imaging the atmosphere. Finally, the reflectivity of a planet’s surface might also influence its temperature.

    The net result is that we don’t know whether any of the planets in a star’s “habitable zone” are actually habitable. But understanding the atmosphere can give us good probabilities, at least.

    The atmosphere can also open a window into the planet’s chemistry and history. On Venus, for example, the huge levels of carbon dioxide and the presence of sulfur dioxide clouds indicate that the planet has an oxidizing environment and that its atmosphere is dominated by volcanic activity. The composition of the gas giants in the outer Solar System likely reflects the gas that was present in the disk that formed the planets early in the Solar System’s history.

    But the most intriguing prospect is that we could find something like Earth, where biological processes produce both methane and the oxygen that ultimately converts it to carbon dioxide. The presence of both in an atmosphere indicates that some process(es) are constantly producing the gases, maintaining a long-term balance. While some geological phenomena can produce both these chemicals, finding them together in an atmosphere would at least be suggestive of possible life.

    Interdisciplinary

    Just the prospect of finding hints of life on other worlds has rapidly transformed the study of exoplanets, since it’s a problem that touches on nearly every area of science. Take the issue of atmospheres and habitability. Even if we understand the composition of a planet’s atmosphere, its temperature won’t just pop out of a simple equation. Distance from the star, type of star, the planet’s rotation, and the circulation of the atmosphere will all play a role in determining conditions. But the climate models that we use to simulate Earth’s atmosphere haven’t been capable of handling anything but the Sun and an Earth-like atmosphere. So extensive work has had to be done to modify them to work with the conditions found elsewhere.

    Similar problems appear everywhere. Geologists and geochemists have to infer likely compositions given little more than a planet’s density and perhaps its atmospheric compositions. Their results need to be combined with atmospheric models to figure out what the surface chemistry of a planet might be. Biologists and biochemists can then take that chemistry and figure out what reactions might be possible there. Meanwhile, the planetary scientists who study our own Solar System can provide insight into how those processes have worked out here.

    “I think it’s part of the Renaissance aspect of exoplanets,” Szentgyorgyi told Ars. “A lot of people now think a lot more broadly, there’s a lot more cross-disciplinary interaction. I find that I’m going to talks about geology, I’m going to talks about the atmospheric chemistry on Titan.”

    The next decade promises incredible progress. A new generation of enormous telescopes is expected to come online, and the James Webb space telescope should devote significant time to imaging exosolar systems.

    NASA/ESA/CSA Webb Telescope annotated


    ____________________________________________
    Other giant 30 meter class telescopes planned

    ESO/E-ELT,39 meter telescope to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level, the only giant 30 meter class telescope for the Northern hemisphere


    ____________________________________________

    We’re likely to end up with much more detailed pictures of some intriguing bodies in our galactic neighborhood.

    The data that will flow from new experiments and new devices will be interpreted by scientists who have already transformed their field. That transformation—from proving that exoplanets exist to establishing a vibrant, multidisciplinary discipline—really took place during the 2010s, which is why it deserves the title “decade of exoplanets.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Ars Technica was founded in 1998 when Founder & Editor-in-Chief Ken Fisher announced his plans for starting a publication devoted to technology that would cater to what he called “alpha geeks”: technologists and IT professionals. Ken’s vision was to build a publication with a simple editorial mission: be “technically savvy, up-to-date, and more fun” than what was currently popular in the space. In the ensuing years, with formidable contributions by a unique editorial staff, Ars Technica became a trusted source for technology news, tech policy analysis, breakdowns of the latest scientific advancements, gadget reviews, software, hardware, and nearly everything else found in between layers of silicon.

    Ars Technica innovates by listening to its core readership. Readers have come to demand devotedness to accuracy and integrity, flanked by a willingness to leave each day’s meaningless, click-bait fodder by the wayside. The result is something unique: the unparalleled marriage of breadth and depth in technology journalism. By 2001, Ars Technica was regularly producing news reports, op-eds, and the like, but the company stood out from the competition by regularly providing long thought-pieces and in-depth explainers.

    And thanks to its readership, Ars Technica also accomplished a number of industry leading moves. In 2001, Ars launched a digital subscription service when such things were non-existent for digital media. Ars was also the first IT publication to begin covering the resurgence of Apple, and the first to draw analytical and cultural ties between the world of high technology and gaming. Ars was also first to begin selling its long form content in digitally distributable forms, such as PDFs and eventually eBooks (again, starting in 2001).

     
  • richardmitnick 11:19 am on December 2, 2019 Permalink | Reply
    Tags: "Astronomers Propose a Novel Method of Finding Atmospheres on Rocky Worlds", , , , , Exoplanets,   

    From NASA/James Webb Space Telescope: “Astronomers Propose a Novel Method of Finding Atmospheres on Rocky Worlds” 

    NASA Webb Header

    NASA/ESA/CSA Webb Telescope annotated

    From NASA/James Webb Space Telescope

    December 02, 2019

    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4366
    cpulliam@stsci.edu

    Webb Telescope Could Detect Heat Signature in a Matter of Hours, They Calculate.

    Rocky planets orbiting red dwarf stars are appealing targets for astronomers since they are both common and easier to study than other planet varieties. One long-standing question is whether such planets can host atmospheres, since they experience a harsh environment of stellar flares and particle winds.

    A team of astronomers calculates that NASA’s upcoming James Webb Space Telescope could potentially detect signs of an atmosphere in just a few hours of observing time. Since the presence of an atmosphere would lower the observed temperature of the planet’s dayside, relative to bare rock, a world with an atmosphere would have a distinct heat signature.

    Although the technique works best for planets too hot to be in the habitable zone, it could have important implications for habitable-zone worlds. If astronomers find that hot, rocky planets can preserve an atmosphere, then cooler planets should be able to as well.

    1
    Illustration of a Cloudy Exoplanet

    When NASA’s James Webb Space Telescope launches in 2021, one of its most anticipated contributions to astronomy will be the study of exoplanets—planets orbiting distant stars. Among the most pressing questions in exoplanet science is: Can a small, rocky exoplanet orbiting close to a red dwarf star hold onto an atmosphere?

    In a series of four papers in The Astrophysical Journal, a team of astronomers proposes a new method of using Webb to determine whether a rocky exoplanet has an atmosphere. The technique, which involves measuring the planet’s temperature as it passes behind its star and then comes back into view, is significantly faster than more traditional methods of atmospheric detection like transmission spectroscopy.

    https://arxiv.org/abs/1907.13138 “Identifying Candidate Atmospheres on Rocky M dwarf Planets via Eclipse Photometry”
    https://arxiv.org/abs/1907.13150 “Identifying Atmospheres on Rocky Exoplanets Through Inferred High Albedo”
    https://arxiv.org/abs/1907.13135 “Identifying Candidate Atmospheres on Rocky M dwarf Planets via Eclipse Photometry”
    https://arxiv.org/abs/1907.13145 “A Scaling Theory for Atmospheric Heat Redistribution on Rocky Exoplanets”
    “We find that Webb could easily infer the presence or absence of an atmosphere around a dozen known rocky exoplanets with less than 10 hours of observing time per planet,” said Jacob Bean of the University of Chicago, a co-author on three of the papers.

    Astronomers are particularly interested in exoplanets orbiting red dwarf stars for a number of reasons. These stars, which are smaller and cooler than the Sun, are the most common type of star in our galaxy. Also, because a red dwarf is small, a planet passing in front of it will appear to block a larger fraction of the star’s light than if the star were larger, like our Sun. This makes the planet orbiting a red dwarf easier to detect through this “transit” technique.

    Red dwarfs also produce a lot less heat than our Sun, so to enjoy habitable temperatures, a planet would need to orbit quite close to a red dwarf star. In fact, to be in the habitable zone — the area around the star where liquid water could exist on a planet’s surface — the planet has to orbit much closer to the star than Mercury is to the Sun. As a result, it will transit the star more frequently, making repeated observations easier.

    But a planet orbiting so close to a red dwarf is subjected to harsh conditions. Young red dwarfs are very active, blasting out huge flares and plasma eruptions. The star also emits a strong wind of charged particles. All of these effects could potentially scour away a planet’s atmosphere, leaving behind a bare rock.

    “Atmospheric loss is the number one existential threat to the habitability of planets,” said Bean.

    Another key characteristic of exoplanets orbiting close to red dwarfs is central to the new technique: They are expected to be tidally locked, meaning they have a permanent dayside and nightside. As a result, we see different phases of the planet at different points in its orbit. When it crosses the face of the star, we see only the planet’s nightside. But when it is about to cross behind the star (an event known as a secondary eclipse), or is just emerging from behind the star, we can observe the dayside.

    If a rocky exoplanet lacks an atmosphere, its dayside would be very hot, just as we see with the Moon or Mercury. However if a rocky exoplanet has an atmosphere, the presence of that atmosphere is expected to lower the dayside temperature that Webb would measure. It could do this in two ways. A thick atmosphere could transport heat from the dayside to the nightside through winds. A thinner atmosphere could still host clouds, which reflect a portion of the incoming starlight thereby lowering the temperature of the planet’s dayside.

    “Whenever you add an atmosphere, you’re going to lower the temperature of the dayside. So if we see something cooler than bare rock, we would infer it’s likely a sign of an atmosphere,” explained Daniel Koll of the Massachusetts Institute of Technology (MIT), the lead author on two of the papers.

    Webb is ideally suited for making these measurements because it has a much larger mirror than other telescopes such as NASA’s Hubble or Spitzer space telescopes, which allows it to collect more light, and it can target the appropriate infrared wavelengths.

    The team’s calculations show that Webb should be able to detect the heat signature of a planet’s atmosphere in one to two secondary eclipses – just a few hours of observing time. In contrast, detecting an atmosphere through spectroscopic observations would typically require eight or more transits for these same planets.

    Transmission spectroscopy, which studies starlight filtered through the planet’s atmosphere, also suffers from interference due to clouds or hazes, which can mask the molecular signatures of the atmosphere. In that case the spectral plot, rather than showing pronounced absorption lines due to molecules, would be essentially flat.

    “In transmission spectroscopy, if you get a flat line, it doesn’t tell you anything. The flat line could mean the universe is full of dead planets that don’t have an atmosphere, or that the universe is full of planets that have a whole range of diverse, interesting atmospheres, but they all look the same to us because they’re cloudy,” said Eliza Kempton of the University of Maryland, a co-author on three of the papers.

    “Exoplanet atmospheres without clouds and hazes are like unicorns – we just haven’t seen them yet, and they may not exist at all,” she added.

    The team emphasized that a cooler than expected dayside temperature would be an important clue, but it would not absolutely confirm an atmosphere exists. Any remaining doubts about the presence of an atmosphere can be ruled out with follow-up studies using other methods like transmission spectroscopy.

    The new technique’s true strength will be in determining what fraction of rocky exoplanets likely have an atmosphere. Approximately a dozen exoplanets that are good candidates for this method were detected during the past year. More are likely to be found by the time Webb is operational.

    “The Transiting Exoplanet Survey Satellite, or TESS, is finding piles of these planets,” stated Kempton.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The secondary eclipse method has one key limitation: it works best on planets that are too hot to be located in the habitable zone. However, determining whether or not these hot planets host atmospheres holds important implications for habitable-zone planets.

    “If hot planets can hold onto an atmosphere, cooler ones should be able to at least as well,” said Koll.

    The James Webb Space Telescope will be the world’s premier space science observatory when it launches in 2021.

    See the full article here .

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    Please help promote STEM in your local schools.

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    The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

    Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.

    NASA Webb NIRCam

    NASA Webb NIRspec

    NASA Webb MIRI

    CSA Webb Fine Guidance Sensor-Near InfraRed Imager and Slitless Spectrograph FGS/NIRISS


    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

    NASA image

    ESA50 Logo large

    Canadian Space Agency

     
  • richardmitnick 10:12 am on November 22, 2019 Permalink | Reply
    Tags: , , , , Exoplanets,   

    From Horizon: “Zeroing in on baby exoplanets could reveal how they form” 

    1

    From Horizon The EU Research and Innovation Magazine

    18 November 2019
    Jon Cartwright

    1
    The way that a young exoplanet interacts with its star’s disc of dust and gas determines the type of exoplanet that will ultimately form. Image credit – NASA/JPL-Caltech/D. Berry

    Twenty-four years ago, Swiss astronomers Michel Mayor and Didier Queloz discovered the first planet orbiting a sun-like star outside our solar system – a milestone recognised by this year’s Nobel prize in physics. Today we know of thousands more ‘exoplanets’, and researchers are now trying to understand when and how they form.

    The known exoplanets are certainly an eclectic bunch. They range in size from small rocky planets, like Earth, to gas giants that are many times bigger than Jupiter.

    Some have meandering orbits, whereas others orbit not one star but two. Some have the modest mass and temperatures that are thought necessary to support life, while some are hellish balls of heat and crushing gravity. Some exoplanets appear to orbit their stars alone, while others orbit along with several other planets, like Earth in our solar system.

    The vast majority of those we’ve discovered so far, however, are Earth- to Jupiter-sized planets that orbit very close to their host stars – often closer than Mercury orbits the sun. Astronomers are trying to understand how these close-orbiting planets came into existence by studying examples in different – preferably early – stages of formation.

    But young, faint exoplanets are hard to make out amid the glare of a highly active parent star. As a group led by Dr Jerome Bouvier at the Grenoble Institute of Planetology and Astrophysics in France asks on its website: ‘Have you ever tried to listen to Sibelius next to a jackhammer?’

    To see through the noise, Dr Bouvier and colleagues are employing some of the world’s most powerful telescope arrays, such as the European Southern Observatory’s Very Large Telescope Interferometer on the Paranal mountain in Chile. Meanwhile, computer simulations of how a young planet disturbs the disc of gas and dust surrounding its nascent star will help them know how to spot young exoplanets in real space.

    2009 ESO VLTI Interferometer image, Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level, • ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).

    Close-orbiting

    The researchers hope that their project, SPIDI, will lead to the discovery of close-orbiting exoplanets as they are forming, when they are about a million years old. ‘One million years – that corresponds to about two days on the scale of a human lifetime,’ said Dr Bouvier.

    One and a half years in, the project is still too new to have delivered any results. But by measuring the properties of close-orbiting exoplanets in their baby phases, the researchers aim to understand how they are born.

    The project will probably not shed light on the formation of exoplanets with other types of orbit, however. And the type of orbit is important, because it determines the conditions on an exoplanet’s surface – and potentially whether it is habitable.

    Each type of exoplanet and exoplanet orbit could be studied individually. But Professor Richard Alexander of the University of Leicester in the UK believes that by studying different types of exoplanets orbiting different stars there is less chance of missing important processes that help make up the big picture of planetary formation.

    ‘To use a very poor analogy: if you could only see one part of an elephant – its trunk, say – you would end up with a very different understanding of elephants to someone who could only see its toes,’ he said. ‘By looking at different types of (exoplanet) systems, we’re trying our best to step back and look at the whole of the “planet-formation elephant”, rather than just one part of it.’

    Star’s disc

    Somehow, the way that a young exoplanet interacts with its star’s disc of dust and gas determines the type of exoplanet that will ultimately form. Prof. Alexander’s project, BuildingPlanS, involves developing computer simulations that predict the effect of different formation processes.

    These simulations can be tested against observations to see whether the processes they describe are accurate.

    The approach is paying off. In one recent study [ads], led by Prof. Alexander’s colleague Dr Dipierro at the University of Leicester, UK, the computer simulations suggested that a ring observed in the disc of a star called Elias 24 is the path cleared by an orbiting, as-yet unidentified, gas-giant planet.

    To really learn something new about planetary formation, however, the researchers want to predict something that has not yet been observed. ‘Then we can use new observations to test the physics directly, and maximise the understanding we gain from all this new knowledge,’ said Prof. Alexander.

    Astrophysicists know that, in the very beginning, planets form as dust and gas accumulate under gravity. But this earliest phase of planet formation is especially hard to study.

    The trouble is that the dust and the gas around young stars each evolve in very complex ways, and studying how they form planets together requires a lot of expertise and computing power. Traditionally, therefore, dust and gas have been simulated as separate processes.

    ​Knotted

    But as Dr Mario Flock of the Max Planck Institute for Astronomy in Heidelberg, Germany, points out, the two processes cannot be truly separated. For instance, the presence of dust can reduce turbulence in the gas, while the turbulence of the gas impacts the size and fragmentation of the dust grains.

    In a project called UFOS, Dr Flock and colleagues are starting to unite gas and dust simulations for the first time, to accurately describe some of the earliest stages of planetary formation. Their hope is to explain some of the features seen in very young stellar disks – spirals and rings – as the footprints of embryonic dust grains clumping together.

    The biggest challenge here, says Dr Flock, is finding the right scales of time and space over which gas and dust interact with the most influence. ‘That requires huge expertise in magneto-hydrodynamics, dust coagulation, numerical tools and high-performance computing.

    ‘If we succeed to link the sites of grain growth and planet formation with current observations – that would be the highest goal,’ he continued. ‘It would help us to understand what’s currently happening in systems we observe now.’

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

     
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