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  • richardmitnick 10:45 am on September 12, 2019 Permalink | Reply
    Tags: "Hubble Reveals Latest Portrait of Saturn", , , , , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Reveals Latest Portrait of Saturn” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    12 September 2019
    Bethany Downer
    ESA/Hubble, Public Information Officer
    Garching, Germany
    Email: Bethany.Downer@partner.eso.org

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Amy Simon
    Goddard Space Flight Center, Greenbelt, Maryland
    amy.simon@nasa.gov

    Mike Wong
    University of California, Berkeley, California
    mikewong@astro.berkeley.edu

    2
    The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on 20 June 2019 as the planet made its closest approach to Earth this year, at approximately 1.36 billion kilometres away.

    NASA/ESA Hubble WFC3

    Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is at its closest distance to Earth. These images, however, are more than just beauty shots. They reveal a planet with a turbulent, dynamic atmosphere. This year’s Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Smaller storms pop into view like popcorn kernels popping in a microwave oven before disappearing just as quickly. Even the planet’s banded structure reveals subtle changes in color. But the latest image shows plenty that hasn’t changed. The mysterious six-sided pattern, called the “hexagon,” still exists on the north pole. Caused by a high-speed jet stream, the hexagon was first discovered in 1981 by NASA’s
    Voyager 1 spacecraft.

    NASA/Voyager 1

    Saturn’s signature rings are still as stunning as ever. The image reveals that the ring system is tilted toward Earth, giving viewers a magnificent look at the bright, icy structure. Hubble resolves numerous ringlets and the fainter inner rings. This image reveals an unprecedented clarity only seen previously in snapshots taken by NASA spacecraft visiting the distant planet. Astronomers will continue their yearly monitoring of the planet to track shifting weather patterns and identify other changes. The second in the yearly series, this image is part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giant planets.

    1
    A. Simon (Goddard Space Flight Center), M.H. Wong (University of California, Berkeley), and the OPAL Team

    Since the Hubble Space Telescope was launched, its goal has been to study not only distant astronomical objects, but also the planets within our Solar System. Hubble’s high-resolution images of our planetary neighbours can only be surpassed by pictures taken from spacecraft that actually visit these bodies. However, Hubble has one advantage over space probes; it can look at these objects periodically and observe them over much longer periods than any passing probe could.

    Saturn hosts many recognisable features, most notably its trademark ring system, which is now tilted towards Earth. This gives us a magnificent view of its bright icy structure. Hubble resolves numerous ringlets and the fainter inner rings. Dutch astronomer Christiaan Huygens first identified the rings in 1655 and thought they were a continuous disk encircling the planet, but we now know them to be composed of orbiting particles of ice and dust. Though all of the gas giants boast rings, Saturn’s are the largest and most spectacular.

    The age of Saturn’s ring system continues to be debated. And, even more perplexingly, it’s unknown what cosmic event formed the rings. There is no consensus among planetary astronomers today.

    Another intriguing feature is the long-lasting hexagon-shaped structure circling the planet’s north pole. It is a mysterious six-sided pattern caused by a high-speed jetstream. The hexagon is so large that four Earths could fit inside its boundaries (there is no similar structure at Saturn’s south pole).

    Other features, however, are not as long-lasting. A large storm in the north polar region spotted by Hubble last year has disappeared. Smaller, convective storms, such as the one just above the centre of the planet’s image, also come and go.

    Saturn’s amber colours come from summer smog-like hazes, produced in photochemical reactions driven by solar ultraviolet radiation. Below the haze lie clouds of ammonia ice crystals, as well as deeper, unseen lower-level clouds of ammonium hydrosulphide and water. The planet’s banded structure is caused by the winds and clouds at different altitudes.

    Saturn’s appearance changes with its seasons, caused by the planet’s 27-degree axial tilt. This image was taken during summer in the planet’s northern hemisphere.

    This image is the second in a yearly series of snapshots taken as part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists to understand the atmospheric dynamics and evolution of our Solar System’s gas giant planets. In Saturn’s case, astronomers will be able to track shifting weather patterns and other changes to identify trends.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 1:14 pm on September 11, 2019 Permalink | Reply
    Tags: "First Water Detected on a Planet in the Habitable Zone", , , , , K2-18b, NASA ESA Hubble,   

    From NASA/ESA Hubble Telescope: “First Water Detected on a Planet in the Habitable Zone” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    11 September 2019

    Dr. Angelos Tsiaras
    UCL CSED
    Cell: +44 (0)7477834386
    Email: atsiaras@star.ucl.ac.uk

    Dr. Ingo Waldmann
    UCL CSED
    Cell: +44 (0)7896320454
    Email: ingo.waldmann@ucl.ac.uk

    Dr. Rebecca Caygill
    UCL Media Relations
    Tel: +44 (0)20 3108 3846
    Cell: +44 (0)7733307596
    Email: r.caygill@ucl.ac.uk

    Bethany Downer
    ESA/Hubble, Public Information Officer
    Garching, Germany
    Email: bethany.downer@partner.eso.org

    Claire Andreoli
    claire.andreoli@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    With data from the NASA/ESA Hubble Space Telescope, water vapour has been detected in the atmosphere of a super-Earth within the habitable zone by University College London (UCL) researchers in a world first. K2-18b, which is eight times the mass of Earth, is now the only planet orbiting a star outside the Solar System, or exoplanet, known to have both water and temperatures that could support life.
    Image credit: ESA/Hubble, M. Kornmesser


    With data from the Hubble Space Telescope, water vapor has been detected in the atmosphere of an exoplanet within the habitable zone of its host star. K2-18b, which is eight times the mass of Earth, is the only planet orbiting a star outside the solar system (or “exoplanet”) known to have both water and temperatures that could support life.
    Credits: NASA’s Goddard Space Flight Center

    The discovery was outlined in two different papers, the first one published on arXiv on September 10, 2019, and the second in Nature Astronomy on September 11, 2019.The discovery is the first successful atmospheric detection of an exoplanet orbiting in its star’s habitable zone, at a distance where water can exist in liquid form.

    First author, Dr Angelos Tsiaras (UCL Centre for Space Exochemistry Data,CSED), said: “Finding water on a potentially habitable world other than Earth is incredibly exciting. K2-18b is not ‘Earth 2.0’ as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question: Is the Earth unique?”

    The team used archive data from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b’s atmosphere [1]. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.

    The authors believe that other molecules, including nitrogen and methane, may be present but they remain undetectable with current observations. Further studies are required to estimate cloud coverage and the percentage of atmospheric water present.

    The planet orbits the cool dwarf star K2-18, which is 110 light years from Earth in the constellation of Leo. Given the high level of activity of its red dwarf star, K2-18b may be more hostile than Earth and is likely to be exposed to more radiation.

    K2-18b was discovered in 2015 and is one of hundreds of super-Earths — planets with masses between those of Earth and Neptune — found by NASA’s Kepler spacecraft. NASA’s TESS mission is expected to detect hundreds more super-Earths in the coming years.

    Co-author Dr Ingo Waldmann (UCL CSED), said: “With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets. This is not only because super-Earths like K2-18b are the most common planets in our Milky Way, but also because red dwarfs — stars smaller than our Sun — are the most common stars.”

    The next generation of space telescopes, including the NASA/ESA/CSA James Webb Space Telescope and ESA’s ARIEL mission, will be able to characterise atmospheres in more detail as they will carry more advanced instruments. ARIEL is expected to launch in 2028 and will observe 1,000 planets in detail to get a truly representative picture of what they are like.

    Professor Giovanna Tinetti (UCL CSED), co-author and Principal Investigator for ARIEL, said: “Our discovery makes K2-18b one of the most interesting targets for future study. Over 4000 exoplanets have been detected but we don’t know much about their composition and nature. By observing a large sample of planets, we hope to reveal secrets about their chemistry, formation and evolution.”

    “This study contributes to our understanding of habitable worlds beyond our Solar System and marks a new era in exoplanet research, crucial to ultimately placing the Earth, our only home, into the greater picture of the Cosmos,” said Dr Tsiaras.
    Notes

    [1] The observations were achieved from 9 transits of K2-18b with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3), as part of the HST proposals 13665 and 14682 (PI: Björn Benneke).

    NASA/ESA Hubble WFC3

    The research was funded by European Research Council and the UK Science and Technology Facilities Council which is part of UKRI.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 10:51 am on September 9, 2019 Permalink | Reply
    Tags: "Hubble Explores the Formation and Evolution of Star Clusters in the Large Magellanic Cloud", , , , , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Explores the Formation and Evolution of Star Clusters in the Large Magellanic Cloud” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    9 September 2019

    Francesco R. Ferraro
    Department of Physics and Astronomy
    University of Bologna
    Tel: +39 051 2095774
    Email: francesco.ferraro3@unibo.it

    Bethany Downer
    ESA/Hubble, Public Information Officer
    Garching, Germany
    Email: Bethany.Downer@partner.eso.org

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    1
    Just as people of the same age can vary greatly in appearance and shape, so do collections of stars or stellar aggregates. New observations from the NASA/ESA Hubble Space Telescope suggest that chronological age alone does not tell the complete story when it comes to the evolution of star clusters.

    3
    NGC 1466 Compass image

    Previous research on the formation and evolution of star clusters has suggested that these systems tend to be compact and dense when they form, before expanding with time to become clusters of both small and large sizes. New Hubble observations in the Large Magellanic Cloud (LMC) galaxy have increased our understanding of how the size of star clusters in the LMC changes with time[1].

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Star clusters are aggregates of many (up to one million) stars. They are active systems in which the mutual gravitational interactions among the stars change their structure over time (known to astronomers as “dynamical evolution”). Because of such interactions, heavy stars tend to progressively sink towards the central region of a star cluster, while low-mass stars can escape from the system. This causes a progressive contraction of the cluster core over different timescales and means that star clusters with the same chronological age can vary greatly in appearance and shape because of their different “dynamical ages”.

    Located nearly 160 000 light-years from Earth, the LMC is a satellite galaxy of the Milky Way which hosts star clusters covering a wide range of ages. This differs from our own Milky Way galaxy which primarily contains older star clusters. The distribution of sizes as a function of age observed for star clusters in the LMC is very puzzling, as the young clusters are all compact, while the oldest systems have both small and large sizes.

    All star clusters, including those in the LMC, have been found to host a special type of re-invigorated stars called blue stragglers [2]. Under certain circumstances, stars receive extra fuel that bulks them up and substantially brightens them. This can happen if one star pulls matter off a neighbour, or if they collide.

    As a result of dynamical aging, heavier stars sink towards the centre of a cluster as the cluster ages, in a process similar to sedimentation, called “central segregation”. Blue stragglers are bright, making them relatively easy to observe, and they have high masses, which means that they are affected by central segregation and can be used to estimate the dynamical age of a star cluster [3].

    Francesco Ferraro of the University of Bologna in Italy and his team used the Hubble Space Telescope to observe blue stragglers in five (coeval) old LMC star clusters with different sizes and succeeded in ranking them in terms of their dynamical age.

    “We demonstrated that different structures of star clusters are due to different levels of dynamical ageing: they are in different physical shape despite the fact that they were born at the same cosmic time. This is the first time that the effect of dynamical ageing has been measured in the LMC clusters” says Ferraro.

    “These findings present intriguing areas for further research, since they reveal a novel and valuable way of reading the observed patterns of LMC star clusters, providing new hints about the cluster formation history in the LMC galaxy,” adds co-author Barbara Lanzoni.
    Notes

    [1] The observations were achieved from a set of long exposures acquired with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) for five old star clusters in the Large Magellanic Cloud galaxy, secured under proposal 14164 (PI: Sarajedini).

    NASA/ESA Hubble WFC3

    NASA Hubble Advanced Camera for Surveys

    [2] Blue stragglers are so called because of their blue colour, and the fact that their evolution lags behind that of their neighbours.

    [3] Blue stragglers combine being relatively bright and having high mass by the standards of globular cluster stars, but they are not the only stars within these clusters that are either bright or massive.

    The team’s paper appears in Nature Astronomy.

    The international team of astronomers in this study consists of F. Ferraro (University of Bologna, Italy and INAF, Italy), B. Lanzoni (University of Bologna, Italy and INAF, Italy), E. Dalessandro (INAF, Italy), M. Cadelano (University of Bologna, Italy and INAF, Italy), S. Raso (University of Bologna, Italy and INAF, Italy), A. Mucciarelli (University of Bologna, Italy and INAF, Italy), G. Beccari (European Southern Observatory, Germany), C. Pallanca (University of Bologna, Italy and INAF, Italy).

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 10:13 am on August 1, 2019 Permalink | Reply
    Tags: "Hubble Uncovers a 'Heavy Metal' Exoplanet Shaped Like a Football", , , , , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Uncovers a ‘Heavy Metal’ Exoplanet Shaped Like a Football” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    August 01, 2019

    Contact:
    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu
    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    David Sing
    Johns Hopkins University, Baltimore, Maryland
    dsing@jhu.edu

    1
    Artists Illustration of WASP 121b. NASA/ ESA Hubble, STScI

    Heavy elements detected for first time escaping exoplanet. The scorching hot exoplanet WASP-121b represents a new twist on the phrase “heavy metal.” There are no loud electric guitar riffs, characteristic of heavy metal music, streaming into space. What is escaping the planet is iron and magnesium gas, dubbed heavy metals, because they are heavier than lightweight hydrogen and helium. The observations by the Hubble Space Telescope represent the first time heavy metal gas has been detected floating away from an exoplanet. A scorching planet, WASP-121b orbits precariously close to a star that is even hotter than our Sun. The intense radiation heats the planet’s upper atmosphere to a blazing 4,600 degrees Fahrenheit. Apparently, the lower atmosphere is still so hot that iron and magnesium remain in gaseous form and stream to the upper atmosphere, where they escape into space on the coattails of hydrogen and helium gas. The sizzling planet is also so close to its star that it is on the cusp of being ripped apart by the star’s intense pull. This hugging distance means that the planet is stretched into a football shape due to gravitational tidal forces.

    How can a planet be “hotter than hot?” The answer is when heavy metals are detected escaping from the planet’s atmosphere, instead of condensing into clouds.

    Observations by NASA’s Hubble Space Telescope reveal magnesium and iron gas streaming from the strange world outside our solar system known as WASP-121b. The observations represent the first time that so-called “heavy metals”—elements heavier than hydrogen and helium—have been spotted escaping from a hot Jupiter, a large, gaseous exoplanet very close to its star.

    Normally, hot Jupiter-sized planets are still cool enough inside to condense heavier elements such as magnesium and iron into clouds.

    But that’s not the case with WASP-121b, which is orbiting so dangerously close to its star that its upper atmosphere reaches a blazing 4,600 degrees Fahrenheit. The temperature in WASP-121b’s upper atmosphere is about 10 times greater than that of any known planetary atmosphere. The WASP-121 system resides about 900 light-years from Earth.

    “Heavy metals have been seen in other hot Jupiters before, but only in the lower atmosphere,” explained lead researcher David Sing of the Johns Hopkins University in Baltimore, Maryland. “So you don’t know if they are escaping or not. With WASP-121b, we see magnesium and iron gas so far away from the planet that they’re not gravitationally bound.”

    Ultraviolet light from the host star, which is brighter and hotter than the Sun, heats the upper atmosphere and helps lead to its escape. In addition, the escaping magnesium and iron gas may contribute to the temperature spike, Sing said. “These metals will make the atmosphere more opaque in the ultraviolet, which could be contributing to the heating of the upper atmosphere,” he explained.

    The sizzling planet is so close to its star that it is on the cusp of being ripped apart by the star’s gravity. This hugging distance means that the planet is football shaped due to gravitational tidal forces.

    “We picked this planet because it is so extreme,” Sing said. “We thought we had a chance of seeing heavier elements escaping. It’s so hot and so favorable to observe, it’s the best shot at finding the presence of heavy metals. We were mainly looking for magnesium, but there have been hints of iron in the atmospheres of other exoplanets. It was a surprise, though, to see it so clearly in the data and at such great altitudes so far away from the planet. The heavy metals are escaping partly because the planet is so big and puffy that its gravity is relatively weak. This is a planet being actively stripped of its atmosphere.”

    The researchers used the observatory’s Space Telescope Imaging Spectrograph to search in ultraviolet light for the spectral signatures of magnesium and iron imprinted on starlight filtering through WASP-121b’s atmosphere as the planet passed in front of, or transited, the face of its home star.

    This exoplanet is also a perfect target for NASA’s upcoming James Webb Space Telescope to search in infrared light for water and carbon dioxide, which can be detected at longer, redder wavelengths.

    NASA/ESA/CSA Webb Telescope annotated

    The combination of Hubble and Webb observations would give astronomers a more complete inventory of the chemical elements that make up the planet’s atmosphere.

    The WASP-121b study is part of the Panchromatic Comparative Exoplanet Treasury (PanCET) survey, a Hubble program to look at 20 exoplanets, ranging in size from super-Earths (several times Earth’s mass) to Jupiters (which are over 100 times Earth’s mass), in the first large-scale ultraviolet, visible, and infrared comparative study of distant worlds.

    The observations of WASP-121b add to the developing story of how planets lose their primordial atmospheres. When planets form, they gather an atmosphere containing gas from the disk in which the planet and star formed. These atmospheres consist mostly of the primordial, lighter-weight gases hydrogen and helium, the most plentiful elements in the universe. This atmosphere dissipates as a planet moves closer to its star.

    “The hot Jupiters are mostly made of hydrogen, and Hubble is very sensitive to hydrogen, so we know these planets can lose the gas relatively easily,” Sing said. “But in the case of WASP-121b, the hydrogen and helium gas is outflowing, almost like a river, and is dragging these metals with them. It’s a very efficient mechanism for mass loss.”

    The results will appear online today in 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

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 10:16 pm on July 22, 2019 Permalink | Reply
    Tags: "10 billion years ago the Milky Way ate a smaller galaxy dubbed Gaia-Enceladus", , , , , , , NASA ESA Hubble   

    From COSMOS Magazine: “10 billion years ago, the Milky Way ate a smaller galaxy dubbed Gaia-Enceladus” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    23 July 2019
    Barry Keily

    1
    Artist’s impression of the merger between the Gaia-Enceladus galaxy and the Milky Way. NASA/ESA/Hubble, CC BY-SA 3.0 IGO

    NASA/ESA Hubble Telescope

    The Milky Way achieved its present form about 10 billion years ago when it merged with a smaller, neighbouring galaxy, new observations and modelling show.

    Researchers led by astrophysicist Carme Gallar of the Universidad de La Laguna in Spain took advantage of measurements taken by the European Space Agency’s Gaia space observatory, which was launched in 2013 for the dedicated purpose of mapping the positions of stars with unprecedented accuracy.

    ESA/GAIA satellite

    They took the new data and subjected it to the two most commonly used techniques for estimating the age of stars – comparison with existing stellar models and what is known as colour-magnitude diagram fitting.

    The approach was applied to Gaia measurements for the galaxy’s two outer rings of stars – known as the blue and red haloes – and what astronomers call its thick central disc.

    The results showed that the stars in the haloes were all more ancient than those in the disc, with those in the former category all exceeding 10 billion years old.

    MIlky Way Galaxy NASA/JPL-Caltech /ESO R. Hurt

    The sharp age difference, the researchers say, confirms and, for the first time, accurately dates a titanic encounter between the progenitor of the Milky Way and a neighbouring, smaller galaxy, dubbed Gaia-Enceladus.

    The different colours of the two haloes are an indication of the iron content of their respective stars. Red stars contain more of it than blue ones. Colour also often indicates great age. Until now, thus, astronomers assumed that the Milky Way’s blue halo was younger than its red one.

    Gallar and colleagues used Gaia data to show that this is not the case. Their modelling reveals that the red and blue haloes contain stars of identical age, and that each region started and ceased star production at about the same time.

    The difference in iron content, the researchers say, is a function of a galaxy size – more massive galaxies contain larger amounts of metal than smaller ones. Thus, they write, the result “means that the stars in the red sequence of the halo, being more metal-rich, must have formed in a galaxy that was more massive than the one where the stars in the blue sequence were formed.”

    The blue halo, they say, represents the remnants of Gaia-Enceladus – a galaxy they estimate to have been around a quarter of the size of the proto Milky Way.

    The research is published in the journal 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

     
  • richardmitnick 8:38 am on July 16, 2019 Permalink | Reply
    Tags: , , , , , NASA ESA Hubble,   

    From NASA/ESA Hubble Telescope: “New Hubble Constant Measurement Adds to Mystery of Universe’s Expansion Rate” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    July 16, 2019

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Louise Lerner
    University of Chicago, Chicago, Illinois
    773-702-8366
    louise@uchicago.edu

    1
    About This Image

    These galaxies are selected from a Hubble Space Telescope program to measure the expansion rate of the universe, called the Hubble constant. The value is calculated by comparing the galaxies’ distances to the apparent rate of recession away from Earth (due to the relativistic effects of expanding space).

    By comparing the apparent brightnesses of the galaxies’ red giant stars with nearby red giants, whose distances were measured with other methods, astronomers are able to determine how far away each of the host galaxies are. This is possible because red giants are reliable milepost markers because they all reach the same peak brightness in their late evolution. And, this can be used as a “standard candle” to calculate distance. Hubble’s exquisite sharpness and sensitivity allowed for red giants to be found in the stellar halos of the host galaxies.

    The red giants were searched for in the halos of the galaxies. The center row shows Hubble’s full field of view. The bottom row zooms even tighter into the Hubble fields. The red giants are identified by yellow circles. Credits: NASA, ESA, W. Freedman (University of Chicago), ESO, and the Digitized Sky Survey

    ________________________________________________________
    2
    About This Image: Credits: NASA, ESA, W. Freedman (University of Chicago), ESO, and the Digitized Sky Survey

    ________________________________________________________

    3

    Red Giant Stars Used as Milepost Markers

    Astronomers have made a new measurement of how fast the universe is expanding, using an entirely different kind of star than previous endeavors. The revised measurement, which comes from NASA’s Hubble Space Telescope, falls in the center of a hotly debated question in astrophysics that may lead to a new interpretation of the universe’s fundamental properties.

    Scientists have known for almost a century that the universe is expanding, meaning the distance between galaxies across the universe is becoming ever more vast every second. But exactly how fast space is stretching, a value known as the Hubble constant, has remained stubbornly elusive.

    Now, University of Chicago professor Wendy Freedman and colleagues have a new measurement for the rate of expansion in the modern universe, suggesting the space between galaxies is stretching faster than scientists would expect. Freedman’s is one of several recent studies that point to a nagging discrepancy between modern expansion measurements and predictions based on the universe as it was more than 13 billion years ago, as measured by the European Space Agency’s Planck satellite.

    ESA/Planck 2009 to 2013

    As more research points to a discrepancy between predictions and observations, scientists are considering whether they may need to come up with a new model for the underlying physics of the universe in order to explain it.

    “The Hubble constant is the cosmological parameter that sets the absolute scale, size and age of the universe; it is one of the most direct ways we have of quantifying how the universe evolves,” said Freedman. “The discrepancy that we saw before has not gone away, but this new evidence suggests that the jury is still out on whether there is an immediate and compelling reason to believe that there is something fundamentally flawed in our current model of the universe.”

    In a new paper accepted for publication in The Astrophysical Journal, Freedman and her team announced a new measurement of the Hubble constant using a kind of star known as a red giant. Their new observations, made using Hubble, indicate that the expansion rate for the nearby universe is just under 70 kilometers per second per megaparsec (km/sec/Mpc). One parsec is equivalent to 3.26 light-years distance.

    This measurement is slightly smaller than the value of 74 km/sec/Mpc recently reported by the Hubble SH0ES (Supernovae H0 for the Equation of State) team using Cepheid variables, which are stars that pulse at regular intervals that correspond to their peak brightness. This team, led by Adam Riess of the Johns Hopkins University and Space Telescope Science Institute, Baltimore, Maryland, recently reported refining their observations to the highest precision to date for their Cepheid distance measurement technique.

    How to Measure Expansion

    A central challenge in measuring the universe’s expansion rate is that it is very difficult to accurately calculate distances to distant objects.

    In 2001, Freedman led a team that used distant stars to make a landmark measurement of the Hubble constant. The Hubble Space Telescope Key Project team measured the value using Cepheid variables as distance markers. Their program concluded that the value of the Hubble constant for our universe was 72 km/sec/Mpc.

    But more recently, scientists took a very different approach: building a model based on the rippling structure of light left over from the big bang, which is called the Cosmic Microwave Background [CMB].

    CMB per ESA/Planck

    The Planck measurements allow scientists to predict how the early universe would likely have evolved into the expansion rate astronomers can measure today. Scientists calculated a value of 67.4 km/sec/Mpc, in significant disagreement with the rate of 74.0 km/sec/Mpc measured with Cepheid stars.

    Astronomers have looked for anything that might be causing the mismatch. “Naturally, questions arise as to whether the discrepancy is coming from some aspect that astronomers don’t yet understand about the stars we’re measuring, or whether our cosmological model of the universe is still incomplete,” Freedman said. “Or maybe both need to be improved upon.”

    Freedman’s team sought to check their results by establishing a new and entirely independent path to the Hubble constant using an entirely different kind of star.

    Certain stars end their lives as a very luminous kind of star called a red giant, a stage of evolution that our own Sun will experience billions of years from now. At a certain point, the star undergoes a catastrophic event called a helium flash, in which the temperature rises to about 100 million degrees and the structure of the star is rearranged, which ultimately dramatically decreases its luminosity. Astronomers can measure the apparent brightness of the red giant stars at this stage in different galaxies, and they can use this as a way to tell their distance.

    The Hubble constant is calculated by comparing distance values to the apparent recessional velocity of the target galaxies — that is, how fast galaxies seem to be moving away. The team’s calculations give a Hubble constant of 69.8 km/sec/Mpc — straddling the values derived by the Planck and Riess teams.

    “Our initial thought was that if there’s a problem to be resolved between the Cepheids and the Cosmic Microwave Background, then the red giant method can be the tie-breaker,” said Freedman.

    But the results do not appear to strongly favor one answer over the other say the researchers, although they align more closely with the Planck results.

    NASA’s upcoming mission, the Wide Field Infrared Survey Telescope (WFIRST), scheduled to launch in the mid-2020s, will enable astronomers to better explore the value of the Hubble constant across cosmic time.

    NASA/WFIRST

    WFIRST, with its Hubble-like resolution and 100 times greater view of the sky, will provide a wealth of new Type Ia supernovae, Cepheid variables, and red giant stars to fundamentally improve distance measurements to galaxies near and far.

    More links at the full article.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 11:27 am on July 11, 2019 Permalink | Reply
    Tags: , , , Black Hole science, , NASA ESA Hubble, Spiral galaxy NGC 3147   

    From NASA/ESA Hubble Telescope: “Hubble Uncovers Black Hole Disk that Shouldn’t Exist” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    July 11, 2019

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Stefano Bianchi
    Università degli Studi Roma Tre, Rome, Italy
    bianchi@fis.uniroma3.it

    Marco Chiaberge
    Space Telescope Science Institute, Baltimore, Maryland
    marcoc@stsci.edu

    1
    NGC 3147 spiral galaxy

    2
    Central Black Hole in NGC 3147, with artist’s illustration

    4
    Compass image of NGC 3147

    __________________________________________________________________________________________
    Hubble Offers Peek at Material Swirling Close to a Black Hole

    Astronomers are always tickled when they find something they didn’t expect to be there. Peering deep into the heart of the majestic spiral galaxy NGC 3147, researchers uncovered a swirling gas disk precariously close to a black hole weighing about 250 million times the mass of our Sun. The surprise is that they thought the black hole was so malnourished, it shouldn’t have such a structure around it. It’s basically a “Mini-Me” version of more powerful disks seen in very active galaxies.

    What’s especially intriguing is that the disk is so deeply embedded in the black hole’s intense gravitational field, its light is being stretched and intensified by the black hole’s powerful grasp. It’s a unique, real-world demonstration of Einstein’s laws of relativity, formulated a century ago.

    Hubble clocked material whirling around the black hole as moving at more than 10% of the speed of light. And, the gas astronomers measured is so entrenched in the gravitational well that light is struggling to climb out, and therefore appears stretched to redder wavelengths.
    __________________________________________________________________________________________

    As if black holes weren’t mysterious enough, astronomers using NASA’s Hubble Space Telescope have found an unexpected thin disk of material furiously whirling around a supermassive black hole at the heart of the magnificent spiral galaxy NGC 3147, located 130 million light-years away.

    The conundrum is that the disk shouldn’t be there, based on current astronomical theories. However, the unexpected presence of a disk so close to a black hole offers a unique opportunity to test Albert Einstein’s theories of relativity. General relativity describes gravity as the curvature of space and special relativity describes the relationship between time and space.

    “We’ve never seen the effects of both general and special relativity in visible light with this much clarity,” said Marco Chiaberge of the European Space Agency, and the Space Telescope Science Institute and Johns Hopkins University, both in Baltimore, Maryland, a member of the team that conducted the Hubble study.

    “This is an intriguing peek at a disk very close to a black hole, so close that the velocities and the intensity of the gravitational pull are affecting how the photons of light look,” added the study’s first author, Stefano Bianchi of Università degli Studi Roma Tre, in Rome, Italy. “We cannot understand the data unless we include the theories of relativity.”

    Black holes in certain types of galaxies like NGC 3147 are malnourished because there is not enough gravitationally captured material to feed them regularly. So, the thin haze of infalling material puffs up like a donut rather than flattening out in a pancake-shaped disk. Therefore, it is very puzzling why there is a thin disk encircling a starving black hole in NGC 3147 that mimics much more powerful disks found in extremely active galaxies with engorged, monster black holes.

    “We thought this was the best candidate to confirm that below certain luminosities, the accretion disk doesn’t exist anymore,” explained Ari Laor of the Technion-Israel Institute of Technology located in Haifa, Israel. “What we saw was something completely unexpected. We found gas in motion producing features we can explain only as being produced by material rotating in a thin disk very close to the black hole.”

    The astronomers initially selected this galaxy to validate accepted models about lower-luminosity active galaxies—those with black holes that are on a meager diet of material. Models predict that an accretion disk forms when ample amounts of gas are trapped by a black hole’s strong gravitational pull. This infalling matter emits lots of light, producing a brilliant beacon called a quasar, in the case of the most well-fed black holes. Once less material is pulled into the disk, it begins to break down, becomes fainter, and changes structure.

    “The type of disk we see is a scaled-down quasar that we did not expect to exist,” Bianchi said. “It’s the same type of disk we see in objects that are 1,000 or even 100,000 times more luminous. The predictions of current models for gas dynamics in very faint active galaxies clearly failed.”

    The disk is so deeply embedded in the black hole’s intense gravitational field that the light from the gas disk is modified, according to Einstein’s theories of relativity, giving astronomers a unique look at the dynamic processes close to a black hole.

    Hubble clocked material whirling around the black hole as moving at more than 10% of the speed of light. At those extreme velocities, the gas appears to brighten as it travels toward Earth on one side, and dims as it speeds away from our planet on the other side (an effect called relativistic beaming). Hubble’s observations also show that the gas is so entrenched in the gravitational well the light is struggling to climb out, and therefore appears stretched to redder wavelengths. The black hole’s mass is around 250 million Suns.

    The researchers used Hubble’s Space Telescope Imaging Spectrograph (STIS) to observe matter swirling deep inside the disk. A spectrograph is a diagnostic tool that divides light from an object into its many individual wavelengths to determine its speed, temperature, and other characteristics at a very high precision. The astronomers needed STIS’s sharp resolution to isolate the faint light from the black-hole region and block out contaminating starlight.

    “Without Hubble, we wouldn’t have been able to see this because the black-hole region has a low luminosity,” Chiaberge said. “The luminosities of the stars in the galaxy outshine anything in the nucleus. So if you observe it from the ground, you’re dominated by the brightness of the stars, which drowns the feeble emission from the nucleus.”

    The team hopes to use Hubble to hunt for other very compact disks around low-wattage black holes in similar active galaxies.

    The team’s paper will appear online today in the Monthly Notices of the Royal Astronomical Society.

    The international team of astronomers in this study consists of Stefano Bianchi (Università degli Studi Roma Tre, Rome, Italy); Robert Antonucci (University of California, Santa Barbara, California); Alessandro Capetti (INAF – Osservatorio Astrofisico di Torino, Pino Torinese, Italy); Marco Chiaberge (Space Telescope Science Institute and Johns Hopkins University, Baltimore, Maryland); Ari Laor (Israel Institute of Technology, Haifa, Israel); Loredana Bassani (INAF/IASF Bologna, Italy); Francisco Carrera (CSIC-Universidad de Cantabria, Santander, Spain); Fabio La Franca, Andrea Marinucci, Giorgio Matt, and Riccardo Middei (Università degli Studi Roma Tre, Roma, Italy); and Francesca Panessa (INAF Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy).

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 11:43 am on July 2, 2019 Permalink | Reply
    Tags: "Atmosphere of Mid-Size Planet Revealed by Hubble and Spitzer", , , , , Mysterious World Is Unlike Anything Found in Our Solar System., NASA ESA Hubble, , One possible explanation is that the planet formed as a 10-Earth-mass rocky core that then accumulated hydrogen very close to its star rather than migrated in which is the conventional wisdom., Plamet GJ 3470 b, Weighing in at 12.6 Earth masses GJ 3470 b is more massive than Earth but less massive than Neptune   

    From NASA/ESA Hubble Telescope: “Atmosphere of Mid-Size Planet Revealed by Hubble and Spitzer” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    1

    Mysterious World Is Unlike Anything Found in Our Solar System.

    Our solar system contains two major classes of planets. Earth is a rocky terrestrial planet, as are Mercury, Venus, and Mars. At about the distance of the asteroid belt, there is a “frost line” where space is so cold more volatile material, like water, can remain frozen. Out here live the gas giants–Jupiter, Saturn, Uranus, and Neptune–which have bulked up on hydrogen and helium and other volatiles.

    Astronomers are curious about a new class of planet not found in the Solar System. Weighing in at 12.6 Earth masses the planet is more massive than Earth, but less massive than Neptune (hence, intermediate between the rocky and gaseous planets in the Solar System). What’s more, the planet, GJ 3470 b, is so close to its red dwarf star that it completes one orbit in just three days! As odd as it seems, planets in this mass range are likely the most abundant throughout the galaxy, based on surveys by NASA’s Kepler space telescope. But they are not found in our own solar system.

    Astronomers enlisted the combined multi-wavelength capabilities of NASA’s Hubble and Spitzer space telescopes to assemble for the first time a “fingerprint” of the chemical composition of GJ 3470 b’s atmosphere, which turns out to be mostly hydrogen and helium, and surprisingly, largely lacking heavier elements. One possible explanation is that the planet formed as a 10-Earth-mass rocky core that then accumulated hydrogen very close to its star, rather than migrated in which is the conventional wisdom for star-hugging planets.

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Björn Benneke
    University of Montreal, Canada
    bbenneke@astro.umontreal.ca

    2
    About This Image

    Structure of Exoplanet GJ 3470 b

    This artist’s illustration shows the theoretical internal structure of the exoplanet GJ 3470 b. It is unlike any planet found in the Solar System. Weighing in at 12.6 Earth masses the planet is more massive than Earth but less massive than Neptune. Unlike Neptune, which is 3 billion miles from the Sun, GJ 3470 b may have formed very close to its red dwarf star as a dry, rocky object. It then gravitationally pulled in hydrogen and helium gas from a circumstellar disk to build up a thick atmosphere. The disk dissipated many billions of years ago, and the planet stopped growing. The bottom illustration shows the disk as the system may have looked long ago. Observations by NASA’s Hubble and Spitzer space telescopes have chemically analyzed the composition of GJ 3470 b’s very clear and deep atmosphere, yielding clues to the planet’s origin. Many planets of this mass exist in our galaxy.

    Two NASA space telescopes have teamed up to identify, for the first time, the detailed chemical “fingerprint” of a planet between the sizes of Earth and Neptune. No planets like this can be found in our own solar system, but they are common around other stars.

    The planet, Gliese 3470 b (also known as GJ 3470 b), may be a cross between Earth and Neptune, with a large rocky core buried under a deep crushing hydrogen and helium atmosphere. Weighing in at 12.6 Earth masses, the planet is more massive than Earth, but less massive than Neptune (which is more than 17 Earth masses).

    Many similar worlds have been discovered by NASA’s Kepler space telescope, whose mission ended in 2018. In fact, 80% of the planets in our galaxy may fall into this mass range. However, astronomers have never been able to understand the chemical nature of such a planet until now, researchers say.

    By inventorying the contents of GJ 3470 b’s atmosphere, astronomers are able to uncover clues about the planet’s nature and origin.

    “This is a big discovery from the planet formation perspective. The planet orbits very close to the star and is far less massive than Jupiter—318 times Earth’s mass—but has managed to accrete the primordial hydrogen/helium atmosphere that is largely “unpolluted” by heavier elements,” said Björn Benneke of the University of Montreal, Canada. “We don’t have anything like this in the solar system, and that’s what makes it striking.”

    Astronomers enlisted the combined multi-wavelength capabilities NASA’s Hubble and Spitzer space telescopes to do a first-of-a-kind study of GJ 3470 b’s atmosphere.

    NASA/Spitzer Infrared Telescope

    This was accomplished by measuring the absorption of starlight as the planet passed in front of its star (transit) and the loss of reflected light from the planet as it passed behind the star (eclipse).

    Planet transit. NASA/Ames

    All totaled, the space telescopes observed 12 transits and 20 eclipses. The science of analyzing chemical fingerprints based on light is called “spectroscopy.”

    “For the first time we have a spectroscopic signature of such a world,” said Benneke. But he is at a loss for classification: Should it be called a “super-Earth” or “sub-Neptune?” Or perhaps something else?

    Fortuitously, the atmosphere of GJ 3470 b turned out to be mostly clear, with only thin hazes, enabling the scientists to probe deep into the atmosphere.

    “We expected an atmosphere strongly enriched in heavier elements like oxygen and carbon which are forming abundant water vapor and methane gas, similar to what we see on Neptune”, said Benneke. “Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen/helium rich composition of the Sun.”

    Other exoplanets called “hot Jupiters” are thought to form far from their stars, and over time migrate much closer. But this planet seems to have formed just where it is today, says Benneke.

    The most plausible explanation, according to Benneke, is that GJ 3470 b was born precariously close to its red dwarf star, which is about half the mass of our Sun. He hypothesizes that essentially it started out as a dry rock, and rapidly accreted hydrogen from a primordial disk of gas when its star was very young. The disk is called a “protoplanetary disk.”

    “We’re seeing an object that was able to accrete hydrogen from the protoplanetary disk, but didn’t runaway to become a hot Jupiter,” said Benneke. “This is an intriguing regime.”

    One explanation is that the disk dissipated before the planet could bulk up further. “The planet got stuck being a sub-Neptune,” said Benneke.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 10:17 am on July 1, 2019 Permalink | Reply
    Tags: , , , , , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Captures the Galaxy’s Biggest Ongoing Stellar Fireworks Show” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    July 01, 2019

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Nathan Smith
    University of Arizona, Tucson, Arizona
    520-621-4513
    nathans@as.arizona.edu

    Jon Morse
    BoldlyGo Institute, New York, New York
    646-380-1813
    jamorse@boldlygo.org

    1

    2
    Compass Image for Eta Carinae
    These images are a composite of separate exposures acquired by the WFC3/UVIS instrument on the Hubble Space Telescope. Several filters were used to sample narrow and wide wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F280N Green: F336W Red: F658N

    Eta Carinae (Observations in UV Light Uncover Magnesium Embedded in Warm Gas)

    Imagine slow-motion fireworks that started exploding 170 years ago and are still continuing. This type of firework is not launched into Earth’s atmosphere, but rather into space by a doomed super-massive star, called Eta Carinae, the largest member of a double-star system. A new view from NASA’s Hubble Space Telescope, which includes ultraviolet light, shows the star’s hot, expanding gases glowing in red, white, and blue. Eta Carinae resides 7,500 light-years away.

    The celestial outburst takes the shape of a pair of ballooning lobes of dust and gas and other filaments that were blown out from the petulant star. The star may have initially weighed more than 150 Suns. For decades, astronomers have speculated about whether it is on the brink of total destruction.

    The fireworks started in the 1840s when Eta Carinae went through a titanic outburst, called the Great Eruption, making it the second-brightest star visible in the sky for over a decade. Eta Carinae, in fact, was so bright that for a time it became an important navigational star for mariners in the southern seas.

    The star has faded since that eruption and is now barely visible to the unaided eye. But the fireworks aren’t over yet because Eta Carinae still survives. Astronomers have used almost every instrument on Hubble over the past 25 years to study the rambunctious star.

    Using Hubble’s Wide Field Camera 3 to map the ultraviolet-light glow of magnesium embedded in warm gas (shown in blue), astronomers were surprised to discover the gas in places they had not seen it before.

    NASA/ESA Hubble WFC3

    Scientists have long known that the outer material thrown off in the 1840s eruption has been heated by shock waves after crashing into the doomed star’s previously ejected material. In the new images, the team had expected to find light from magnesium coming from the same complicated array of filaments as seen in the glowing nitrogen (shown in red). Instead, a completely new luminous magnesium structure was found in the space between the dusty bipolar bubbles and the outer shock-heated nitrogen-rich filaments.

    “We’ve discovered a large amount of warm gas that was ejected in the Great Eruption but hasn’t yet collided with the other material surrounding Eta Carinae,” explained Nathan Smith of Steward Observatory at the University of Arizona in Tucson, Arizona, lead investigator of the Hubble program. “Most of the emission is located where we expected to find an empty cavity. This extra material is fast, and it ‘ups the ante’ in terms of the total energy for an already powerful stellar blast.”

    The newly revealed gas is important for understanding how the eruption began, because it represents the fast and energetic ejection of material that may have been expelled by the star shortly before the expulsion of the bipolar lobes. Astronomers need more observations to measure exactly how fast the material is moving and when it was ejected.

    The streaks visible in the blue region outside the lower-left lobe are a striking feature in the image. These streaks are created when the star’s light rays poke through the dust clumps scattered along the bubble’s surface. Wherever the ultraviolet light strikes the dense dust, it leaves a long, thin shadow that extends beyond the lobe into the surrounding gas. “The pattern of light and shadow is reminiscent of sunbeams that we see in our atmosphere when sunlight streams past the edge of a cloud, though the physical mechanism creating Eta Carinae’s light is different,” noted team member Jon Morse of BoldlyGo Institute in New York.

    This technique of searching in ultraviolet light for warm gas could be used to study other stars and gaseous nebulas, the researchers say.

    “We had used Hubble for decades to study Eta Carinae in visible and infrared light, and we thought we had a pretty full accounting of its ejected debris. But this new ultraviolet-light image looks astonishingly different, revealing gas we did not see in other visible-light or infrared images,” Smith said. “We’re excited by the prospect that this type of ultraviolet magnesium emission may also expose previously hidden gas in other types of objects that eject material, such as protostars or other dying stars. Only Hubble can take these kinds of pictures.”

    Eta Carinae has had a violent history, prone to chaotic eruptions that blast parts of itself into space like an interstellar geyser. One explanation for the monster star’s antics is that the convulsions were caused by a complex interplay of as many as three stars, all gravitationally bound in one system. In this scenario, the most massive member would have swallowed one of the stars, igniting the massive Great Eruption of the mid-1800s. Evidence for that event lies in the huge, expanding bipolar lobes of hot gas surrounding the system.

    A fortuitous trick of nature also allowed astronomers in a previous Hubble study to analyze the Great Eruption in detail. Some of the light from the eruption took an indirect path to Earth and is just arriving now. The wayward light was heading away from our planet when it bounced off dust clouds lingering far from the turbulent stars and was rerouted to Earth, an effect called a “light echo.”

    The stellar behemoth will eventually reach its fireworks show finale when it explodes as a supernova. This may have already happened, although the geyser of light from such a brilliant blast hasn’t yet reached Earth.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 10:43 am on June 16, 2019 Permalink | Reply
    Tags: , , , , NASA ESA Hubble   

    From NASA/ESA Hubble Telescope: “Hubble Observes Tiny Galaxy with Big Heart” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope


    From NASA/ESA Hubble Telescope

    13 June 2019
    Bethany Downer
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Email: bethany.downer@partner.eso.org

    1
    Nestled within this field of bright foreground stars lies ESO 495-21, a tiny galaxy with a big heart. ESO 495-21 may be just 3000 light-years across, but that is not stopping the galaxy from furiously forming huge numbers of stars. It may also host a supermassive black hole; this is unusual for a galaxy of its size, and may provide intriguing hints as to how galaxies form and evolve.

    2
    Ground-based view of the sky around the galaxy ESO 495-21

    Located about 30 million light-years away in the constellation of Pyxis (The Compass), ESO 495-21 is a dwarf starburst galaxy — this means that it is small in size, but ablaze with rapid bursts of star formation. Starburst galaxies form stars at exceptionally high rates, creating stellar newborns of up to 1000 times faster than the Milky Way.

    Hubble has studied the bursts of activity within ESO 495-21 several times. Notably, the space telescope has explored the galaxy’s multiple super star clusters, very dense regions only a few million years old and packed with massive stars. These spectacular areas can have a huge impact on their host galaxies. Studying them allows astronomers to investigate the earliest stages of their evolution, in a bid to understand how massive stars form and change throughout the Universe.

    As well as hosting the cosmic fireworks that are super star clusters, ESO 495-21 also may harbour a supermassive black hole at its core. Astronomers know that almost every large galaxy hosts such an object at its centre, and, in general, the bigger the galaxy, the more massive the black hole. Our home galaxy, the Milky Way, houses a supermassive black hole, Sagittarius A*, which is over four million times as massive as the Sun. ESO 495-21, also known as Henize 2-10) is a dwarf galaxy, only three percent the size of the Milky Way, and yet there are indications that the black hole at its core is over a million times as massive as the Sun — an extremely unusual scenario.

    This black hole may offer clues as to how black holes and galaxies evolved in the early Universe. The origin of the central supermassive black holes in galaxies is still a matter of debate — do the galaxies form first and then crush material at their centres into black holes, or do pre-existing black holes gather galaxies around them? Do they evolve together — or could the answer be something else entirely?

    With its small size, indistinct shape, and rapid starburst activity, astronomers think ESO 495-21 may be an analogue for some of the first galaxies to have formed in the cosmos. Finding a black hole at the galaxy’s heart is therefore a strong indication that black holes may have formed first, with galaxies later developing and evolving around them.

    The data comprising this image were gathered by two of the instruments aboard the NASA/ESA Hubble Space Telescope: the Advanced Camera for Surveys and already decommissioned Wide Field Planetary Camera 2.

    NASA Hubble Advanced Camera forSurveys

    NASA/Hubble WFPC2. No longer in service.

    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 Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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