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  • richardmitnick 11:23 am on June 20, 2017 Permalink | Reply
    Tags: , , , , , Keck Observatory, , Two Distinct "Species" of Exoplanets Illuminated, Unexpected Classification of Exoplanets Discovered   

    From Keck: “Unexpected Classification of Exoplanets Discovered -Two Distinct “Species” of Exoplanets Illuminated” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    6.20.17
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    Since the mid-1990s, when the first planet around another sun-like star was discovered, astronomers have amassed an ever-expanding collection of nearly 3,500 confirmed exoplanets.

    In a new Caltech-led study, researchers have classified these exoplanets in much the same way that biologists identify new animal species and found the majority of exoplanets fall into two distinct groups: rocky Earth-like planets and larger mini-Neptunes. The team used data from W. M. Keck Observatory and NASA’s Kepler mission.

    NASA/Kepler Telescope

    “This is a major new division in the family tree of planets, analogous to discovering that mammals and lizards are distinct branches on the tree of life,” says Andrew Howard, professor of astronomy at Caltech and a principal investigator of the new research.

    1
    Assembly Line of Planets: This diagram illustrates how planets are assembled and sorted into two distinct size classes. First, the rocky cores of planets are formed from smaller pieces. Then, the gravity of the planets attracts hydrogen and helium gas. Finally, the planets are “baked” by the starlight and lose some gas. At a certain mass threshold, planets retain the gas and become gaseous mini-Neptunes; below this threshold, the planets lose all their gas, becoming rocky super-Earths. CREDIT: NASA/KEPLER/CALTECH (R. HURT)

    The lead author of the new study, to be published in The Astronomical Journal, is Benjamin J. (B. J.) Fulton, a graduate student in Howard’s group.

    In essence, their research shows that our galaxy has a strong preference for either rocky planets up to 1.75 times the size of Earth or gas-enshrouded mini-Neptune worlds, which are from 2 to 3.5 times the size of Earth (or somewhat smaller than Neptune). Our galaxy rarely makes planets with sizes in between these two groups.

    “Astronomers like to put things in buckets,” says Fulton. “In this case, we have found two very distinct buckets for the majority of the Kepler planets.”

    Since the Kepler mission launched in 2009, it has identified and confirmed more than 2,300 exoplanets. Kepler specializes in finding planets close to their stars, so the majority of these planets orbit more closely than Mercury, which circles the sun at roughly one-third of the Earth-sun distance.

    Most of these close-in planets were found to be roughly between the size of Earth and Neptune, which is about four times the size of Earth. But, until now it was not known they fall into two distinct size groups.

    “In the solar system, there are no planets with sizes between Earth and Neptune,” says Erik Petigura, co-author of the study and a Hubble Postdoctoral Fellow at Caltech. “One of the great surprises from Kepler is that nearly every star has at least one planet larger than Earth but smaller than Neptune. We’d really like to know what these mysterious planets are like and why we don’t have them in our own solar system.”

    Kepler finds planets by looking for telltale dips in starlight as they pass in front of their stars. The size of the dip is correlated with the size of the planet. But in order to precisely know the planets’ sizes, the sizes of the stars must be measured.

    The Caltech team—together with colleagues from several institutions, including UC Berkeley, the University of Hawaii, Harvard University, Princeton University, and the University of Montreal—took a closer look at the Kepler planets’ sizes with the help of Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES).

    Keck HIRES

    They spent years gathering HIRES spectral data on the stars hosting 2,000 Kepler planets, allowing them to obtain precise measurements of the sizes of the stars; these measurements, in turn, helped determine more accurate sizes for the planets orbiting those stars.

    “Before, sorting the planets by size was like trying to sort grains of sand with your naked eye,” says Fulton. “Getting the spectra from Keck Observatory is like going out and grabbing a magnifying glass. We could see details that we couldn’t before.”

    With Keck Observatory’s HIRES data, the researchers were able to measure the sizes of the 2,000 planets with four times more precision than what had been achieved previously.

    When they examined the distribution of planet sizes, they found a surprise: a striking gap between the groups of rocky Earths and mini-Neptunes. Though a few planets fall into the gap, the majority do not.

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    Mind the Exoplanet Gap: Researchers using data from the W. M. Keck Observatory and NASA’s Kepler mission have discovered a gap in the distribution of planet sizes, indicating that most planets discovered by Kepler so far fall into two distinct size classes: the rocky Earths and super-Earths (similar to Kepler-452b), and the mini-Neptunes (similar to Kepler-22b). This histogram shows the number of planets per 100 stars as a function of planet size relative to Earth. CREDIT: NASA/AMES/CALTECH/UNIVERSITY OF HAWAII (B. J. FULTON).

    The cause of the gap is not clear, but the scientists have come up with two possible explanations. The first is based on the idea that nature likes to make a lot of planets roughly the size of Earth. Some of those planets, for reasons that are not fully understood, end up acquiring enough gas to “jump the gap” and become gaseous mini-Neptunes.

    “A little bit of hydrogen and helium gas goes a very long way. So, if a planet acquires only one percent of hydrogen and helium in mass, that’s enough to jump the gap,” says Howard. “These planets are like rocks with big balloons of gas around them. The hydrogen and helium that’s in the balloon doesn’t really contribute to the mass of the system as a whole, but it contributes to the volume in a tremendous way, making the planets a lot bigger in size.”

    The second possible reason that planets don’t land in the gap has to do with planets losing gas. If a planet does happen to acquire just a little bit of gas—the right amount to place it in the gap—that gas can be burned off when exposed to radiation from the host star.

    “A planet would have to get lucky to land in the gap, and then if it did, it probably wouldn’t stay there,” says Howard. “It’s unlikely for a planet to have just the right amount of gas to land in the gap. And those planets that do have enough gas can have their thin atmospheres blown off. Both scenarios likely carve out the gap in planet sizes that we observe.”

    4
    New Branch in Exoplanet Family Tree: This sketch illustrates a family tree of exoplanets. Planets are born out of swirling disks of gas and dust called protoplanetary disks. The disks give rise to giant planets like Jupiter as well as smaller planets mostly between the size of Earth and Neptune. Researchers using data from the W.M. Keck Observatory and NASA’s Kepler mission discovered that these smaller planets can be cleanly divided into two size groups: the rocky Earth-like planets and super-Earths, and the gaseous mini-Neptunes. CREDIT: NASA/KEPLER/CALTECH (T. PYLE)

    In the future, the researchers plan to study the heavy-element content of these planets to learn more about their composition. “We’re living in a golden age of planetary astronomy because we are finding thousands of planets around other stars,” says Petigura. “We are currently working to understand what these mini-Neptunes are made of, which should help explain why these planets form so easily around other stars and why they didn’t form around the sun.”

    The study, titled The California-Kepler Survey. III. A Gap in the Radius of Distribution of Small Planets, was funded by NASA and the National Science Foundation.

    About HIRES

    The High-Resolution Echelle Spectrometer (HIRES) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many “stripes” of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding planets orbiting other stars. Astronomers also use HIRES to study distant galaxies and quasars, finding clues to the Big Bang. 
Support for this project was provided by the William J. and Dorothy K. O’Neill Foundation, and Joseph and Deborah Schell.

    See the full article here .

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    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 11:20 am on June 19, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory, , NASA Releases Kepler Survey Catalog with Hundreds of New Planet Candidates   

    From NASA: “NASA Releases Kepler Survey Catalog with Hundreds of New Planet Candidates” 

    NASA image
    NASA

    June 19, 2017
    Felicia Chou
    Headquarters, Washington
    202-358-0257
    felicia.chou@nasa.gov

    Michele Johnson
    Ames Research Center, California’s Silicon Valley
    650-604-6882
    michele.johnson@nasa.gov

    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    NASA’s Kepler space telescope team has identified 219 new planet candidates, 10 of which are near-Earth size and in the habitable zone of their star. Credits: NASA/JPL-Caltech

    NASA’s Kepler space telescope team has released a mission catalog of planet candidates that introduces 219 new planet candidates, 10 of which are near-Earth size and orbiting in their star’s habitable zone, which is the range of distance from a star where liquid water could pool on the surface of a rocky planet.

    NASA/Kepler Telescope

    This is the most comprehensive and detailed catalog release of candidate exoplanets, which are planets outside our solar system, from Kepler’s first four years of data. It’s also the final catalog from the spacecraft’s view of the patch of sky in the Cygnus constellation.

    With the release of this catalog, derived from data publicly available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.

    Additionally, results using Kepler data suggest two distinct size groupings of small planets. Both results have significant implications for the search for life. The final Kepler catalog will serve as the foundation for more study to determine the prevalence and demographics of planets in the galaxy, while the discovery of the two distinct planetary populations shows that about half the planets we know of in the galaxy either have no surface, or lie beneath a deep, crushing atmosphere – an environment unlikely to host life.

    The findings were presented at a news conference Monday at NASA’s Ames Research Center in California’s Silicon Valley.

    “The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs – planets with roughly the same size and orbit as Earth,” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate. “Understanding their frequency in the galaxy will help inform the design of future NASA missions to directly image another Earth.”

    The Kepler space telescope hunts for planets by detecting the minuscule drop in a star’s brightness that occurs when a planet crosses in front of it, called a transit.

    This is the eighth release of the Kepler candidate catalog, gathered by reprocessing the entire set of data from Kepler’s observations during the first four years of its primary mission. This data will enable scientists to determine what planetary populations – from rocky bodies the size of Earth, to gas giants the size of Jupiter – make up the galaxy’s planetary demographics.

    To ensure a lot of planets weren’t missed, the team introduced their own simulated planet transit signals into the data set and determined how many were correctly identified as planets. Then, they added data that appear to come from a planet, but were actually false signals, and checked how often the analysis mistook these for planet candidates. This work told them which types of planets were overcounted and which were undercounted by the Kepler team’s data processing methods.

    “This carefully-measured catalog is the foundation for directly answering one of astronomy’s most compelling questions – how many planets like our Earth are in the galaxy?” said Susan Thompson, Kepler research scientist for the SETI Institute in Mountain View, California, and lead author of the catalog study.

    One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. The team found a clean division in the sizes of rocky, Earth-size planets and gaseous planets smaller than Neptune. Few planets were found between those groupings.

    Using the W. M. Keck Observatory in Hawaii, the group measured the sizes of 1,300 stars in the Kepler field of view to determine the radii of 2,000 Kepler planets with exquisite precision.


    Keck Observatory, Mauna Kea, Hawaii, USA

    “We like to think of this study as classifying planets in the same way that biologists identify new species of animals,” said Benjamin Fulton, doctoral candidate at the University of Hawaii in Manoa, and lead author of the second study. “Finding two distinct groups of exoplanets is like discovering mammals and lizards make up distinct branches of a family tree.”

    It seems that nature commonly makes rocky planets up to about 75 percent bigger than Earth. For reasons scientists don’t yet understand, about half of those planets take on a small amount of hydrogen and helium that dramatically swells their size, allowing them to “jump the gap” and join the population closer to Neptune’s size.

    The Kepler spacecraft continues to make observations in new patches of sky in its extended mission, searching for planets and studying a variety of interesting astronomical objects, from distant star clusters to objects such as the TRAPPIST-1 system of seven Earth-size planets, closer to home.

    Ames manages the Kepler missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

    For more information about the Kepler mission, visit:

    https://www.nasa.gov/kepler

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 2:33 pm on June 6, 2017 Permalink | Reply
    Tags: , , , , , , Keck Observatory   

    From CFHT: “Astronomers prove what separates true stars from wannabes” 

    CFHT icon
    Canada France Hawaii Telescope

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    HONOLULU — Astronomers have shown what separates real stars from the wannabes. Not in Hollywood, but out in the universe.

    6.5.17

    Dr. Roy Gal
    University of Hawaii at Manoa
    +1 301-728-8637
    rgal@ifa.hawaii.edu

    Dr. Trent Dupuy
    The University of Texas at Austin
    +1 318-344-0975
    tdupuy@astro.as.utexas.edu

    Dr. Michael Liu
    University of Hawaii at Manoa
    +1 808-956-6666
    mliu@ifa.hawaii.edu

    Mari-Ela Chock
    W. M. Keck Observatory
    808-554-0567
    mchock@keck.hawaii.edu

    1
    Professor Michael Liu stands in front of WIRCam, CFHT’s infrared camera that was used for this decade long study.

    “When we look up and see the stars shining at night, we are seeing only part of the story,” said Trent Dupuy of the University of Texas at Austin and a graduate of the Institute for Astronomy at the University of Hawaii at Manoa.

    “Not everything that could be a star ‘makes it,’ and figuring out why this process sometimes fails is just as important as understanding when it succeeds.

    Dupuy is the lead author of the study and will present his research today in a news conference at the semi-annual meeting of the American Astronomical Society in Austin.

    Stars form when a cloud of gas and dust collapses due to gravity, and the resulting ball of matter becomes hot enough and dense enough to sustain nuclear fusion at its core. Fusion produces huge amounts of energy — it’s what makes stars shine. In the Sun’s case, it’s what makes most life on Earth possible.

    But not all collapsing gas clouds are created equal. Sometimes, the collapsing cloud makes a ball that isn’t dense enough to ignite fusion. These ‘failed stars’ are known as brown dwarfs.

    This simple division between stars and brown dwarfs has been used for a long time. In fact, astronomers have had theories about how massive the collapsing ball has to be in order to form a star (or not) for over 50 years. However, the dividing line in mass has never been confirmed by experiment.

    Now, astronomers Dupuy and Michael Liu of the University of Hawaii, who is a co-author of the study, have done just that. They found that an object must weigh at least 70 Jupiters in order to start hydrogen fusion. If it weighs less, the star does not ignite and becomes a brown dwarf instead.

    How did they reach that conclusion? For a decade, the two studied 31 faint brown dwarf binaries (pairs of these objects that orbit each other) using two powerful telescopes in Hawaii — the W. M. Keck Observatory and Canada-France-Hawaii telescopes — as well as data from the Hubble Space Telescope.

    4
    Magnificent Failures: Discovery of a rare brown-dwarf eclipsing binary. http://astro.phy.vanderbilt.edu/~stassuk/research.htm

    NASA/ESA Hubble Telescope

    Their goal was to measure the masses of the objects in these binaries, since mass defines the boundary between stars and brown dwarfs. Astronomers have been using binaries to measure masses of stars for more than a century. To determine the masses of a binary, one measures the size and speed of the stars’ orbits around an invisible point between them where the pull of gravity is equal (known as the “center of mass”). However, binary brown dwarfs orbit much more slowly than binary stars, due to their lower masses. And because brown dwarfs are dimmer than stars, they can only be well studied with the world’s most powerful telescopes.

    To measure masses, Dupuy and Liu collected images of the brown-dwarf binaries over several years, tracking their orbital motions using high-precision observations. They used the 10-meter Keck Observatory telescope, along with its laser guide star adaptive optics system, and the Hubble Space Telescope, to obtain the extremely sharp images needed to distinguish the light from each object in the pair.

    However, the price of such zoomed-in, high-resolution images is that there is no reference frame to identify the center of mass. Wide-field images from the Canada-France-Hawaii Telescope containing hundreds of stars provided the reference grid needed to measure the center of mass for every binary. The precise positions needed to make these measurements are one of the specialties of WIRCam, the wide field infrared camera at CFHT. “Working with Trent Dupuy and Mike Liu over the last decade has not only benefited their work but our understanding of what is possible with WIRCam as well” says Daniel Devost, director of science operations at CFHT. “This is one of the first programs I worked on when I started at CFHT so this makes this discovery even more exciting.”

    The result of the decade-long observing program is the first large sample of brown dwarf masses. The information they have assembled has allowed them to draw a number of conclusions about what distinguishes stars from brown dwarfs.

    Objects heavier than 70 Jupiter masses are not cold enough to be brown dwarfs, implying that they are all stars powered by nuclear fusion. Therefore 70 Jupiters is the critical mass below which objects are fated to be brown dwarfs. This minimum mass is somewhat lower than theories had predicted but still consistent with the latest models of brown dwarf evolution.

    In addition to the mass cutoff, they discovered a surface temperature cutoff. Any object cooler than 1,600 Kelvin (about 2,400 degrees Fahrenheit) is not a star, but a brown dwarf.

    This new work will help astronomers understand the conditions under which stars form and evolve — or sometimes fail. In turn, the success or failure of star formation has an impact on how, where, and why solar systems form.

    “As they say, good things come to those who wait. While we’ve had many interesting brown dwarf results over the past 10 years, this large sample of masses is the big payoff. These measurements will be fundamental to understanding both brown dwarfs and stars for a very long time,” concludes Liu.

    This research will be published in The Astrophysical Journal Supplement.
    Additional information

    University of Hawaii press release.
    Scientific Paper on the arXiv

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    Keck 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

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 2:40 pm on May 31, 2017 Permalink | Reply
    Tags: Andrea Ghez UCLA, , , , , Keck Observatory, New Method of Searching for Fifth Force   

    From Keck: “New Method of Searching for Fifth Force” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    1

    W. M. Keck Observatory data leads to first of its kind test of Einstein’s theory of General Relativity

    A UCLA-led team has discovered a new way of probing the hypothetical fifth force of nature using two decades of observations at W. M. Keck Observatory, the world’s most scientifically productive ground-based telescope.

    There are four known forces in the universe: electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force. Physicists know how to make the first three work together, but gravity is the odd one out. For decades, there have been theories that a fifth force ties gravity to the others, but no one has been able to prove it thus far.

    “This is really exciting. It’s taken us 20 years to get here, but now our work on studying stars at the center of our galaxy is opening up a new method of looking at how gravity works,” said Andrea Ghez, Director of the UCLA Galactic Center Group and co-author of the study.

    3
    Andrea Ghez, UCL

    The research is published in the current issue of Physical Review Letters.

    Ghez and her co-workers analyzed extremely sharp images of the center of our galaxy taken with Keck Observatory’s adaptive optics (AO). Ghez used this cutting-edge system to track the orbits of stars near the supermassive black hole located at the center of the Milky Way. Their stellar path, driven by gravity created from the supermassive black hole, could give clues to the fifth force.

    “By watching the stars move over 20 years using very precise measurements taken from Keck Observatory data, you can see and put constraints on how gravity works. If gravitation is driven by something other than Einstein’s theory of General Relativity, you’ll see small variations in the orbital paths of the stars,” said Ghez.

    3
    The orbits of two stars, S0-2 and S0-38 located near the Milky Way’s supermassive black hole will be used to test Einstein’s theory of General Relativity and potentially generate new gravitational models. IMAGE CREDIT: S. SAKAI/A.GHEZ/W. M. KECK OBSERVATORY/ UCLA GALACTIC CENTER GROUP.

    This is the first time the fifth force theory has been tested in a strong gravitational field such as the one created by the supermassive black hole at the center of the Milky Way. Historically, measurements of our solar system’s gravity created by our sun have been used to try and detect the fifth force, but that has proven difficult because its gravitational field is relatively weak.

    “It’s exciting that we can do this because we can ask a very fundamental question – how does gravity work?” said Ghez. “Einstein’s theory describes it beautifully well, but there’s lots of evidence showing the theory has holes. The mere existence of supermassive black holes tells us that our current theories of how the universe works are inadequate to explain what a black hole is.”

    Ghez and her team, including lead author Aurelien Hees and co-author Tuan Do, both of UCLA, are looking forward to summer of 2018. That is when the star S0-2 will be at its closest distance to our galaxy’s supermassive black hole. This will allow the team to witness the star being pulled at maximum gravitational strength – a point where any deviations to Einstein’s theory is expected to be the greatest.

    About Adaptive Optics
    W. M. Keck Observatory is a distinguished leader in the field of adaptive optics (AO), a breakthrough technology that removes the distortions caused by the turbulence in the Earth’s atmosphere. Keck Observatory pioneered the astronomical use of both natural guide star (NGS) and laser guide star adaptive optics (LGS AO) and our current systems now deliver images three to four times sharper than the Hubble Space Telescope. AO has imaged the four massive planets orbiting the star HR8799, measured the mass of the giant black hole at the center of our Milky Way Galaxy, discovered new supernovae in distant galaxies, and identified the specific stars that were their progenitors.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 7:22 am on May 27, 2017 Permalink | Reply
    Tags: , , Fifth force, Keck Observatory, , , UCLA Galactic Center Group   

    From KECK: “New Method of Searching for Fifth Force” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    1
    The orbits of two stars, S0-2 and S0-38 located near the Milky Way’s supermassive black hole will be used to test Einstein’s theory of General Relativity and potentially generate new gravitational models. IMAGE CREDIT: S. SAKAI/A.GHEZ/W. M. KECK OBSERVATORY/ UCLA GALACTIC CENTER GROUP

    W. M. Keck Observatory Data Leads To First Of Its Kind Test of Einstein’s Theory of General Relativity.

    May 26, 2017
    No writer credit found.

    A UCLA-led team has discovered a new way of probing the hypothetical fifth force of nature using two decades of observations at W. M. Keck Observatory, the world’s most scientifically productive ground-based telescope.

    There are four known forces in the universe: electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force. Physicists know how to make the first three work together, but gravity is the odd one out. For decades, there have been theories that a fifth force ties gravity to the others, but no one has been able to prove it thus far.

    “This is really exciting. It’s taken us 20 years to get here, but now our work on studying stars at the center of our galaxy is opening up a new method of looking at how gravity works,” said Andrea Ghez, Director of the UCLA Galactic Center Group and co-author of the study.

    The research is published in the current issue of Physical Review Letters.

    Ghez and her co-workers analyzed extremely sharp images of the center of our galaxy taken with Keck Observatory’s adaptive optics (AO). Ghez used this cutting-edge system to track the orbits of stars near the supermassive black hole located at the center of the Milky Way.

    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    Their stellar path, driven by gravity created from the supermassive black hole, could give clues to the fifth force.

    “By watching the stars move over 20 years using very precise measurements taken from Keck Observatory data, you can see and put constraints on how gravity works. If gravitation is driven by something other than Einstein’s theory of General Relativity, you’ll see small variations in the orbital paths of the stars,” said Ghez.

    2
    Pictured above: UCLA Professor of Astrophysics and Galactic Center Group Director Andrea Ghez, a Keck Observatory astronomer and recipient of the 2015 Bakerian Medal. IMAGE CREDIT: KYLE ALEXANDER

    This is the first time the fifth force theory has been tested in a strong gravitational field such as the one created by the supermassive black hole at the center of the Milky Way. Historically, measurements of our solar system’s gravity created by our sun have been used to try and detect the fifth force, but that has proven difficult because its gravitational field is relatively weak.

    “It’s exciting that we can do this because we can ask a very fundamental question – how does gravity work?” said Ghez. “Einstein’s theory describes it beautifully well, but there’s lots of evidence showing the theory has holes. The mere existence of supermassive black holes tells us that our current theories of how the universe works are inadequate to explain what a black hole is.”

    Ghez and her team, including lead author Aurelien Hees and co-author Tuan Do, both of UCLA, are looking forward to summer of 2018. That is when the star S0-2 will be at its closest distance to our galaxy’s supermassive black hole. This will allow the team to witness the star being pulled at maximum gravitational strength – a point where any deviations to Einstein’s theory is expected to be the greatest.

    About Adaptive Optics

    W. M. Keck Observatory is a distinguished leader in the field of adaptive optics (AO), a breakthrough technology that removes the distortions caused by the turbulence in the Earth’s atmosphere.

    Keck Observatory pioneered the astronomical use of both natural guide star (NGS) and laser guide star adaptive optics (LGS AO) and our current systems now deliver images three to four times sharper than the Hubble Space Telescope. AO has imaged the four massive planets orbiting the star HR8799, measured the mass of the giant black hole at the center of our Milky Way Galaxy, discovered new supernovae in distant galaxies, and identified the specific stars that were their progenitors.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 8:16 am on April 20, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory, Keco Cosmic Web Imager from Caltech   

    From Keck Observatory: “W. M. Keck Observatory Achieves First Light with New Instrument” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    4.20.17
    MEDIA CONTACT:
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    “THIS IS AN INSTRUMENT THAT IS BREAKING RECORDS IN SO MANY WAYS, AND I’M REALLY HAPPY THAT WE CAN NOW SHARE THIS EXCITEMENT.”

    W. M. Keck Observatory Achieves
    First Light with New Instrument
    Integral field spectrograph to provide unprecedented view
    of deep space

    `
    Luca Rizzi, support astronomer for W. M. Keck Observatory, gives perspective on KCWI’s size. This Caltech-built instrument is about as large as an ice cream truck and weighs five tons.

    2
    3
    KCWI built AT CALTECH

    W. M. Keck Observatory has captured the very first successful science data from its newest, cutting-edge instrument, the Keck Cosmic Web Imager (KCWI).

    KCWI captures three-dimensional data, as opposed to the traditional two-dimensional image or spectrum of conventional instruments. In a single observation, it records an image of the object at multiple wavelengths allowing scientists to explore both the spatial dimension (as in an image) and the spectral dimension (or color) of an object.

    “I’m thrilled to see this new instrument,” said Keck Observatory Director Hilton Lewis. “It takes years to design and build these very sophisticated instruments. KCWI is a superb example of the application of the most advanced technology to enable the hardest science. I believe it has the potential to transform the science that we do, and continue to keep Keck Observatory right at the forefront of astronomical research.”

    KCWI is extremely sensitive, specifically designed to capture high-resolution spectra of ultra-faint celestial bodies with unprecedented detail. It is able to differentiate even the slightest changes in spectral color with a great degree of accuracy.

    This powerful capability is key for astronomers because a highly-detailed spectral image allows them to identify a cosmic object’s characteristics, including its temperature, motion, density, mass, distance, chemical composition, and more.

    KCWI is designed to study the wispy currents of gas that connect galaxies. The ability to study this “cosmic web” is the driving principle behind KCWI’s design. However, it will also be used to study many other astronomical phenomena including young stars, evolved stars, supernovae, star clusters, and galaxies.

    “I’m incredibly excited. These moments happen only a few times in one’s life as a scientist,” said Principal Investigator Christopher Martin, physics professor at Caltech who developed the concept of KCWI. “To take a powerful new instrument, a tool for looking at the universe in a completely novel way, and install it at the greatest observatory in the world is a dream for an astronomer. This is one of the best days of my life.”

    Martin flew in from California to join the Keck Observatory team as they worked to achieve the milestone moment on Tuesday night, April 11. The following morning, at 2:30 a.m., KCWI successfully achieved first light, with a spectral image of the core of the globular cluster Messier 3.

    4
    This “first-light” image from KCWI (middle) shows more than 100 stars in the core of the globular cluster Messier 3 (right). The boxes are positioned around some of the stars, and connect to their corresponding spectra. The green outlines showcase the highest spectral-resolution setting of KCWI. Each star has a rich spectrum of absorption lines (the dips) that contain information about the velocity and chemical composition of the star.

    Since then, Keck Observatory’s team has been working diligently to install and test KCWI on Keck II, one of the twin 10-meter Keck Observatory telescopes.

    “KCWI will really raise the bar in terms of Keck Observatory’s capabilities,” said Anne Kinney, chief scientist at Keck Observatory. “I think it’ll become the most popular instrument we have because it will be able to do a great breadth of science, increasing our ability to understand and untangle the effects of dark matter in galaxy formation.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 12:34 pm on April 14, 2017 Permalink | Reply
    Tags: , , , , , , Keck Observatory   

    From Caltech: “Keck Cosmic Web Imager Achieves ‘First Light'” 

    Caltech Logo

    Caltech

    04/14/2017

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Keck Observatory

    A Caltech-built instrument designed to study the mysteries of the cosmic web—streams of gas connecting galaxies—has captured its first image, an event astronomers call “first light.” The instrument, called the Keck Cosmic Web Imager, or KCWI, was recently installed on the W. M. Keck Observatory in Hawaii.

    2
    Hector Rodriguez, senior mechanical technician, works on the Keck Cosmic Web Imager in a clean room at Caltech. Credit: Caltech

    KCWI captures highly detailed spectral images of cosmic objects to reveal their temperature, motion, density, mass, distance, chemical composition, and more. The instrument is designed to study the wispy cosmic web; it will also observe many other astronomical phenomena, including young stars, evolved stars, supernovas, star clusters, and galaxies.

    “I’m incredibly excited. These moments happen only a few times in one’s life as a scientist,” says principal investigator Christopher Martin, professor of physics at Caltech. “To take a powerful new instrument, a tool for looking at the universe in a completely novel way, and install it at the greatest observatory in the world is a dream for an astronomer. This is one of the best days of my life.”

    Martin and his Caltech team, in collaboration with scientists at UC Santa Cruz and with industrial partners, designed and built the 5-ton instrument—about the size of an ice cream truck. It was then shipped from California to Hawaii on January 12. Since then, Keck Observatory’s team has been working diligently to install and test KCWI on Keck II, one of the twin 10-meter Keck Observatory telescopes.

    “KCWI will really raise the bar in terms of Keck Observatory’s capabilities,” says Anne Kinney, chief scientist at Keck Observatory. “I think it will become the most popular instrument we have, because it will be able to do a great breadth of science, increasing our ability to understand and untangle the effects of dark matter in galaxy formation.”

    The W. M. Keck Observatory is a private 501(c)3 nonprofit organization and a scientific partnership of Caltech, the University of California, and NASA.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
    Caltech buildings

     
  • richardmitnick 7:30 am on April 6, 2017 Permalink | Reply
    Tags: , , , , , Keck Observatory,   

    From Swinburne: “The monster galaxy that grew up too fast” 

    Swinburne U bloc

    Swinburne University

    6 April 2017
    Lea Kivivali
    +61 3 9214 5428
    lkivivali@swin.edu.au

    1
    Artist’s impression of galaxy ZF-COSMOS-20115. The galaxy has likely blown off all the gas that caused its rapid star formation and mass growth and rapidly turned into a compact red galaxy. *
    No image credit.

    An international team of astronomers has, for the first time, spotted a massive, inactive galaxy from a time when the Universe was only 1.65 billion years old.

    Astronomers expect most galaxies from this epoch to be low-mass minnows, busily forming stars. However, this galaxy is ‘a monster’ and inactive, according to Professor Karl Glazebrook, Director of Swinburne’s Centre for Astrophysics and Supercomputing, who led the team.

    The researchers found that within a short time period this massive galaxy, known as ZF-COSMOS-20115, formed all its stars (three times more than our Milky Way today) through an extreme star-burst event. But it stopped forming stars only a billion years after the Big Bang to become a quiescent or ‘red and dead’ galaxy – common in our Universe today, but not expected to exist at this ancient epoch.

    The galaxy is also small and extremely dense, it has 300 billion stars crammed into a region of space about the same size as the distance from the Sun to the nearby Orion Nebula.

    Astrophysicists are still debating just how galaxies stop forming stars. Until recently, models suggested dead galaxies or ‘red nuggets’ such as this should only exist from around three billion years after the Big Bang.

    “This discovery sets a new record for the earliest massive red galaxy. It is an incredibly rare find that poses a new challenge to galaxy evolution models to accommodate the existence of such galaxies much earlier in the Universe.”

    This research builds on an earlier Swinburne study that suggested such dead galaxies could exist based on finding dim red objects in extremely deep near-infrared images.

    MOSFIRE spectrograph studies the faintest, most distant galaxies

    In this latest study, astronomers used the W M Keck telescopes in Hawai’i to confirm the signatures of these galaxies, through the new and unique MOSFIRE spectrograph. They took deep spectra at near-infrared wavelengths to seek out the definitive features signifying the presence of old stars and a lack of active star formation.

    Keck Observatory, Mauna Kea, Hawaii, USA

    Keck/MOSFIRE on Keck 1, Mauna Kea, Hawaii, USA

    “We used the most powerful telescope in the world, but we still needed to stare at this galaxy for more than two nights to reveal its remarkable nature,” co-author Professor Vy Tran, from Texas A&M University, says.

    Even with large telescopes such as the Keck with a 10 metre mirror, a long viewing time is required to detect absorption lines which are very weak compared to the more prominent emission lines generated by star-forming active galaxies.

    “By collecting enough light to measure this galaxy’s spectrum, we decipher the cosmic narrative of what stars and elements are present in these galaxies and construct a timeline of when they formed their stars,” Professor Tran says.

    The observed star-formation rate of this galaxy produces less than one fifth the mass of the Sun a year in new stars, but at its peak 700 million years previously this galaxy formed 5000 times faster.

    “This huge galaxy formed like a firecracker in less than 100 million years, right at the start of cosmic history,” Professor Glazebrook says.

    “It quickly made a monstrous object, then just as suddenly it quenched and turned itself off. As to how it did this we can only speculate. This fast life and death so early in the Universe is not predicted by our modern galaxy formation theories.”

    Co-author Dr Corentin Schreiber of Leiden University, who first measured the spectrum, speculates that these early firecrackers are obscured behind a veil of dust and that future observations using sub-millimetre wave telescopes will spot these.

    ”Sub-millimetre waves are emitted by the hot dust which blocks other light and will tell us when these firecrackers exploded and how big a role they played in developing the primordial universe,” says Dr Schreiber.

    With the launch of the James Webb Space Telescope in 2018, astronomers will be able to build up large samples of these dead galaxies due to its high sensitivity, large mirror, and the advantage of no atmosphere in space.

    NASA/ESA/CSA Webb Telescope annotated

    This research has been published in Nature.

    The team included researchers from:

    Swinburne University of Technology, Australia; Leiden University, Netherlands; University of Geneva, Switzerland; Texas A & M University, USA; Macquarie University, Australia; Australian Astronomical Observatory; Max Planck Institute for Astronomy, Germany; The Australian National University.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Swinburne U Campus

    Swinburne is a large and culturally diverse organisation. A desire to innovate and bring about positive change motivates our students and staff. The result is in an institution that grows and evolves each year.

     
  • richardmitnick 8:40 am on March 30, 2017 Permalink | Reply
    Tags: , , Keck Observatory, , , TXS 0828+193, TXS0211−122   

    From Keck and IAC via phys.org: “Expanding super bubble of gas detected around massive black holes in the early universe” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    2

    Instituto de Astrofísica e Ciências do Espaço

    phys.org

    1
    Left – Composite image of a large gas blob of glowing hydrogen gas, shown by a Lyman-alpha optical image (colored yellow) from the Subaru telescope (NAOJ). A galaxy located in the blob is visible in a broadband optical image (white) from the Hubble Space Telescope and an infrared image from the Spitzer Space Telescope (red). Finally, the Chandra X-ray Observatory image in blue shows evidence for a growing supermassive black hole in the center of the galaxy. Radiation and outflows from this active black hole are powerful enough to light up and heat the gas in the blob.

    In a study led by Sandy Morais, a PhD student at Instituto de Astrofísica e Ciências do Espaço and Faculty of Sciences of the University of Porto (FCUP), researchers found massive super bubbles of gas and dust around two distant radio galaxies about 11.5 billion light years away.

    Andrew Humphrey (IA & University of Porto), the leader of the project, commented: “By studying violent galaxies like these, we have gained a new insight into the way supermassive black holes affect the evolution of the galaxies in which they reside.”

    The researchers used two of the largest observatories available today, the Keck II (Hawaii) and the Gran Telescópio de Canárias (GTC), to observe TXS0211−122 and TXS 0828+193, two powerful radio galaxies, harboring the most energetic type of Active Galactic Nuclei (AGN) known. This type of galaxy houses the most massive black holes and have the most powerful continuous energy ejections known.

    The team discovered expanding super bubbles of gas around each of TXS 0211-122 and TXS 0828+193, most likely caused by “feedback” activity whereby the AGN injects vast quantities of energy into its host galaxy, creating a powerful wind that sweeps up gas and dust into an expanding super bubble.

    Study of the symbiosis between the supermassive black hole and the galaxy is a key to understanding the evolution of the most massive galaxies. Ultraviolet emission from the black hole’s accretion disk can inhibit star formation temporarily, by ionizing the Interstellar medium, and the great outflows of gas towards the black hole can lead to permanent inhibition of star formation.

    1
    Schematic of the expanding gas Bubble, over a radio image of the full field of TXS 0828+193. Credit: Morais et al. 2017

    More information: S. G. Morais et al. Ionization and feedback in Lyα haloes around two radio galaxies at∼ 2.5, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stw2926

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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

    Institute of Astrophysics and Space Sciences

    Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

     
    • RIcardo Reis 5:49 am on March 31, 2017 Permalink | Reply

      This research was NOT made by Instituto de Astrofisica de Canarias in Spain, but by Instituto de Astrofísica e Ciências do Espaço in Portugal.
      In fact, if you check the paper (https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stw2926), this research has no one from IAC.

      Like

    • richardmitnick 7:47 am on March 31, 2017 Permalink | Reply

      Thank you very much for the correction. I did not read far enough and got myself stuck in the acronym. I believe that I have sufficiently corrected the post. Please look at it again and let me know what you think.

      Thanks again for your help.

      Like

  • richardmitnick 6:50 pm on March 7, 2017 Permalink | Reply
    Tags: Keck Observatory, , Oort cloud comet C/2014 Q2 also called Lovejoy   

    From Keck: “NASA Study Using Keck Telescope Hints at Possible Change in Water ‘Fingerprint’ of Comet” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    March 6, 2017.
    Contact:
    Elizabeth Zubritsky
    NASA Goddard Space Flight Center
    elizabeth.a.zubritsky@nasa.gov

    Rich Matsuda
    W. M. Keck Observatory
    (808) 881-3822
    communications@keck.hawaii.edu

    1
    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun. Credit: Courtesy of Damian Peach

    A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.

    Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.

    Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.

    The team focused on Lovejoy’s water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the “D” in HDO. From these measurements, the researchers calculated the D-to-H ratio – a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system. Researchers also use the D-to-H value to try to understand how much of Earth’s water may have come from comets versus asteroids.

    The scientists compared their findings from the Keck observations with another team’s observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference: After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant. This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

    “The change we saw with this comet is surprising, and highlights the need for repeated measurements of D-to-H in comets at different positions in their orbits to understand all the implications,” said Lucas Paganini, a researcher with the Goddard Center for Astrobiology and lead author of the study, available online in the Astrophysical Journal Letters.

    Changes in the water production are expected as comets approach the sun, but previous understanding suggested that the release of these different forms of water normally rise or fall more-or-less together, maintaining a consistent D-to-H value. The new findings suggest this may not be the case.

    “If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth’s water compared to asteroids,” Paganini said, “especially, if these are based on a single measurement of the D-to-H value in cometary water.”

    The production of HDO in comets has historically been difficult to measure, because HDO is a much less abundant form of water. Lovejoy, for example, released on the order of 1,500 times more H2O than HDO. Lovejoy’s brightness made it possible to measure HDO when the comet passed near Earth, and the improved detectors that are being installed in some ground-based telescopes will permit similar measurements in fainter comets in the future.

    The apparent change in Lovejoy’s D-to-H may be caused by the higher levels of energetic processes – such as radiation near the sun – that might have altered the characteristics of water in surface layers of the comet. In this case, a different D-to-H value might indicate that the comet has “aged” into a different stage of its lifecycle. Alternatively, prior results might have ignored possible chemical alteration occurring in the comet’s tenuous atmosphere.

    “Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun,” said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author of the study. “The infrared technique provides a snapshot of the comet’s output by measuring the production of H2O and HDO simultaneously. This is especially important because it eliminates many sources of systematic uncertainty.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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

     
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