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  • richardmitnick 3:15 pm on September 21, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory,   

    From COSMOS: “Tougher, shinier mirrors boost telescope power” 

    Cosmos Magazine bloc

    COSMOS Magazine

    21 September 2017
    Andrew Masterson

    1
    The 10-metre mirror array at Hawaii’s Keck Telescope. Laurie Hatch, UCSC

    The world’s big astronomical telescopes could soon all get a performance upgrade without the need for installing bigger mirrors, thanks to a collaboration between materials scientists and astronomers at the University of California, Santa Cruz, in the US.

    One key property of the mirrors used in astronomical telescopes is, of course, reflectiveness. Another, however, is durability – and the intersection of the two represents a trade-off.

    Most big telescopes use mirrors coated in aluminium, which is a comparatively tough material that can survive the sometimes harsh environments in which observatories are situated, as well as being able to withstand the potentially damaging effects of being manhandled.

    Silver makes for a much more efficient mirror because it is much more reflective. However, it is also fragile, and prone to damage and corrosion.

    Tackling this problem after a conversation with a despairing astronomer, a team led by materials scientist Nobuhiko Kobayashi has formulated a tough but ultra-thin coating that can keep silver protected without reducing or distorting its reflective properties.

    The team formulated several new alloys, using various combinations of fluoride, magnesium and aluminium oxides. These were then deposited on a silver surface, using an electron beam, in a molecule-by-molecule process called atomic layer deposition.

    The best-performing formulation – which rejoices in the name MgAl2O4, Al2O3 – enabled high reflectance at wavelengths between 340 nanometres and the mid-infrared spectrum. It remained stable even when exposed to 80% humidity and 80 degree Celsius temperatures for 10 days in a row.

    Both the specific formulation and the application method have been patented by their inventors. The mechanical limit of the process at present means the largest mirror that can be coated has a diameter of 0.9 metres.

    Kobayashi and his colleagues are working on doubling this – an upper limit, they say, that will allow the mirrors in even the world’s largest telescopes to be converted to silver. The main mirrors of the Keck Telescope in Hawaii, for instance, comprise a 10-metre span, but are made up of 1.8 metre-wide components.

    “It is by far the cheapest way to make our telescopes effectively bigger,” says co-author Michael Bolte. “The reason we want bigger telescopes is to collect more light, so if your mirrors reflect more light it’s like making them bigger.”

    The research is published in the SPIE Digital Library.

    See the full article here .

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  • richardmitnick 7:55 am on September 16, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory, , NASA IRTF, ,   

    From Goddard: “How Two Ground-based Telescopes Support NASA’s Cassini Mission” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Sept. 11, 2017
    Elizabeth Zubritsky
    elizabeth.a.zubritsky@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    When NASA’s Cassini spacecraft plunges into the atmosphere of Saturn on Sept. 15, ending its 20 years of exploration, astronomers will observe the giant planet from Earth, giving context to Cassini’s final measurements.

    “The whole time Cassini is descending, we’ll be on the ground, taking data and learning about conditions on Saturn,” said Don Jennings, a senior scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-investigator for a Cassini instrument called the Composite Infrared Spectrometer.

    1
    The aftermath of a massive storm that erupted in Saturn’s northern hemisphere in December 2010 continues to be tracked by researchers, including observations planned using the new high-resolution iSHELL instrument at NASA’s Infrared Telescope Facility. Credits: NASA/JPL-Caltech/SSI

    This farewell is fitting for a mission that has been supported by similar observations throughout its lifetime. NASA’s Infrared Telescope Facility, or IRTF, and the W. M. Keck Observatory, in which NASA is a partner, have provided crucial contributions from the summit of Maunakea in Hawaii. Other U.S. and international telescopes also have investigated the Saturn system, complementing and enhancing the mission.

    NASA Infrared Telescope facility Mauna Kea, Hawaii, USA, 4,207 m (13,802 ft) above sea level

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level

    “IRTF and other facilities have provided direct support to the Cassini–Huygens mission and made it possible to link that data to decades’ worth of earlier and ongoing ground-based studies,” said IRTF director John Rayner.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    “Through its daytime observing capabilities IRTF is able to provide almost year-round monitoring of planets in support of NASA missions.”

    Ground-based observations of Titan, the giant planet’s largest moon, helped with preparations for the Huygens probe mission early in Cassini’s exploration of the Saturn system. The probe was released after Cassini entered Saturn orbit and descended through Titan’s thick atmosphere to land on the surface.

    A coordinated ground campaign was organized to study Titan’s atmosphere and surface, to measure the wind speed and direction, to look at atmospheric chemistry and to provide global imaging.

    Eight facilities worldwide participated, observing before, during and after the Huygens probe mission, led by the European Space Agency. These included the Keck Observatory, which captured high-resolution images of the atmospheric weather patterns on Titan, and the IRTF, which helped determine the direction of Titan’s winds.

    “Ground-based observing played a crucial role, because at that time, it was the only way to determine the direction of Titan’s winds, which had the potential to affect Huygens’ descent to the surface,” said Goddard’s Theodor (Ted) Kostiuk, who led those observations at the IRTF and is now an emeritus scientist. “The Voyager flyby provided some information about Titan, but wind direction was one thing it could not tell us.”

    IRTF continues to be used for long-term studies of Saturn and Titan and their atmospheres, and to investigate Saturn’s moons, extending and complementing Cassini findings. The facility’s recently installed high-resolution infrared instrument, called iSHELL, will be deployed for ongoing studies of the aftermath of a massive storm that broke out in Saturn’s northern hemisphere in 2010. With its very high spectral resolution, iSHELL has been optimized for the study of planetary atmospheres.

    Cassini also has received plenty of aloha from the Keck Observatory, which has provided many sharp images and spectra of Saturn’s most famous feature – its rings. These studies are made possible by the high spatial resolution of Keck’s large aperture combined with a state-of-the-art adaptive optics system to correct for distortions caused by Earth’s atmosphere.

    “It’s been exciting to be involved in ground support of the Cassini orbiter over these many years,” said Observing Support Manager Randy Campbell of Keck Observatory. “This mission has given us an opportunity to work together toward a better understanding of some of the most beautiful and enigmatic objects in the night sky, Saturn and its moons.”

    During the summer of 2017, the Cassini team used Keck Observatory to take near-infrared spectroscopic data of the regions near Saturn’s equator, just as Cassini was diving between Saturn and its rings during its final orbits. The team also took Keck data of the polar magnetic fields to better understand the planet’s auroras, which are similar to Earth’s northern and southern lights. The Keck Observatory data will be used to verify Cassini’s data to provide a sort of “ground-truth” calibration of some of the on-board instruments of the orbiter.

    After Cassini, ground-based studies will continue, building on everything the spacecraft observed, and keeping the discoveries coming.

    For more information about NASA’s Infrared Telescope Facility, visit:

    http://irtfweb.ifa.hawaii.edu/

    For more information about the Keck Observatory, visit:

    http://www.keckobservatory.org/

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 2:19 pm on August 18, 2017 Permalink | Reply
    Tags: , , , Brown dwarf binaries, , , Goal was to measure the masses of the objects in these binaries, Keck Observatory,   

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

    CFHT icon
    Canada France Hawaii Telescope

    June 5, 2017 [Just presented in social media.]

    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

    “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.”

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

    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.


    Keck Observatory, Maunakea, Hawaii, USA

    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.

    See the full article here .
    See the U Hawaii press release here .

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    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 4:20 am on August 10, 2017 Permalink | Reply
    Tags: , , , , ESO/HARPS, , , Keck Observatory, Tau Ceti, U Hertfordshire   

    From Keck Observatory: “Four Earth-Sized Planets Found Orbiting the Nearest Sun-Like Star” 

    Keck Observatory

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

    Keck Observatory

    August 9, 2017
    MEDIA CONTACT:
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    1
    This illustration compares the four planets detected around the nearby star Tau Ceti (top) and the inner planets of our solar system (bottom). Credit: CREDIT: F. FENG, UNIVERSITY OF HERTFORDSHIRE, UNITED KINGDOM

    A new study by an international team of astronomers reveals that Tau Ceti, the nearest Sun-like star about 12 light years away from the Sun, has four Earth-sized planets orbiting it.

    These planets have masses as low as 1.7 Earth mass, making them among the smallest planets ever detected around the nearest Sun-like stars. Two of them are Super-Earths located in the habitable zone of the star and thus could support liquid surface water.

    The data were obtained by using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at the European Southern Observatory in Chile, combined with the High-Resolution Echelle Spectrometer (HIRES) at the W. M. Keck Observatory on Maunakea, Hawaii.

    ESO/HARPS at La Silla

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

    Keck HIRES

    “HIRES is one of only a few spectrometers in the world that have routinely delivered the level of radial velocity precision needed for this kind of work,” said co-author Dr. Steve Vogt, professor of astronomy and astrophysics at University of California, Santa Cruz. “And it is one of only two instruments in the world, the other being HARPS, that has been able to deliver this precision level for over a decade. It is a very unique facility in the exoplanet discovery field.”

    The four planets were detected by observing the wobbles in the movement of Tau Ceti. This wobble, known as the Doppler effect, happens when a planet’s gravity slightly tugs at its host star as it orbits.

    Measuring Tau Ceti’s wobbles required techniques sensitive enough to detect variations in its movement as small as 30 centimeters per second. The smaller the planet, the weaker its gravitational pull on its host star, and the harder it is to detect the star’s wobble.

    “We are getting tantalizingly close to the 10 centimeters per second limit required for detecting Earth analogs,” said Dr. Fabo Feng from the University of Hertfordshire in the United Kingdom and lead author of the study. “Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earth’s habitability through comparison with these analogs.”

    The outer two planets around Tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets.

    The same team also investigated Tau Ceti four years ago in 2013, when Dr. Mikko Tuomi led an effort in developing data analysis techniques and used the star as a benchmark case.

    “We came up with an ingenious way of telling the difference between signals caused by planets and those caused by a star’s activity. We realized that we could see how a star’s activity differed at different wavelengths, then used that information to separate this activity from signals of planets,” said Dr. Tuomi.

    “We have painstakingly improved the sensitivity of our techniques and could rule out two of the signals our team identified in 2013 as planets. But no matter how we look at the star, there seems to be at least four rocky planets orbiting it,” Dr. Tuomi added. “We are slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface. This enabled us to essentially verify the existence of the two outer, potentially habitable, planets in the system.”

    Sun-like stars are thought to be the best targets for searching for habitable Earth-sized planets due to their similarity to the Sun. Unlike more common smaller stars such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked, showing the same side to the star at all times.

    Tau Ceti is very similar to the Sun in its size and brightness, and they both host multi-planet systems. If the outer two planets are found to be habitable, Tau Ceti could be an optimal target for interstellar colonization, as seen in science fiction.

    “Such weak signals of planets almost the size of the Earth cannot be seen without using advanced statistical and modeling approaches. We have introduced new methods to remove the noise in the data in order to reveal the weak planetary signals,” said Dr. Feng.

    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.

    Science paper:
    Color difference makes a difference: four planet candidates around tau Ceti, The Astrophysical Journal.

    Authors

    Fabo Feng, Mikko Tuomi, Hugh Jones – University of Hertfordshire, UK
    John Barnes – The Open University, UK
    Guillem Anglada-Escude – Queen Mary University ofLondon, UK
    Steve Vogt – University of California at Santa Cruz, USA
    Paul Butler – Carnegie Institute of Washington, USA

    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

    Keck NASA

    Keck Caltech

     
  • richardmitnick 11:32 am on August 2, 2017 Permalink | Reply
    Tags: , , , , Keck Observatory, New Storm Makes Surprise Appearance on Neptune   

    From Keck: “New Storm Makes Surprise Appearance on Neptune” 

    Keck Observatory

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

    Keck Observatory

    August 2, 2017
    No writer credit found

    1
    Images of Neptune taken during twilight observing revealed an extremely large bright storm system near Neptune’s equator (labeled ‘cloud complex’ in the upper figure), a region where astronomers have never seen a bright cloud. The center of the storm complex is ~9,000 km across, about 3/4 the size of Earth, or 1/3 of Neptune’s radius. The storm brightened considerably between June 26 and July 2, as noted in the logarithmic scale of the images taken on July 2. N. MOLTER/I. DE PATER, UC BERKELEY/C. ALVAREZ, W. M. KECK OBSERVATORY.

    Extremely large, bright storm system caught on camera at W. M. Keck Observatory.

    Striking images of a storm system nearly the size of Earth have astronomers doing a double-take after pinpointing its location near Neptune’s equator, a region where no bright cloud has ever been seen before.

    “Seeing a storm this bright at such a low latitude is extremely surprising,” said Ned Molter, a graduate student at University of California, Berkeley, who spotted the storm complex during a test run of twilight observing at W. M. Keck Observatory on Maunakea, Hawaii. “Normally, this area is really quiet and we only see bright clouds in the mid-latitude bands, so to have such an enormous cloud sitting right at the equator is spectacular.”

    This massive storm system is about 9,000 kilometers in length, or 1/3 the size of Neptune’s radius, spanning at least 30 degrees in both latitude and longitude. Molter observed it getting much brighter between June 26 and July 2.

    “Historically, very bright clouds have occasionally been seen on Neptune, but usually at latitudes closer to the poles, around 15 to 60 degrees north or south,” said Molter’s advisor, Professor Imke de Pater of UC Berkeley’s Astronomy Department. “Never before has a cloud been seen at, or so close to the equator, nor has one ever been this bright.”

    2

    At first, de Pater (pictured above) thought it was the same Northern Cloud Complex seen by the Hubble Space Telescope in 1994, after the iconic Great Dark Spot, imaged by Voyager 2 in 1989, had disappeared. But de Pater says measurements of its locale do not match, signaling that this cloud complex is different from the one Hubble first saw more than two decades ago.

    A huge, high-pressure, dark vortex system anchored deep in Neptune’s atmosphere may be what’s causing the colossal cloud cover. As gases rise up in a vortex, they cool down. When its temperature drops below the condensation temperature of a condensable gas, that gas condenses out and forms clouds, just like water on Earth. On Neptune we expect methane clouds to form.

    As with every planet, winds in Neptune’s atmosphere vary drastically with latitude, so if there is a big bright cloud system that spans many latitudes, something must hold it together, such as a dark vortex. Otherwise, the clouds would shear apart.

    “This big vortex is sitting in a region where the air, overall, is subsiding rather than rising,” said de Pater. “Moreover, a long-lasting vortex right at the equator would be hard to explain physically.”

    If it is not tied to a vortex, the system may be a huge convective cloud, similar to those seen occasionally on other planets like the huge storm on Saturn that was detected in 2010. Although

    one would also then expect the storm to have smeared out considerably over a week’s time.

    “This shows that there are extremely drastic changes in the dynamics of Neptune’s atmosphere, and perhaps this is a seasonal weather event that may happen every few decades or so,” said de Pater.

    Neptune is the windiest planet in our solar system, with the fastest observed wind speeds at the equator reaching up to a violent 1000 miles per hour. To put this into perspective, a Category 5 hurricane has wind speeds of 156 miles per hour. Neptune orbits the Sun every 160 years, and one season is about 40 years.

    KECK VISITING SCHOLARS PROGRAM

    The discovery of Neptune’s mysterious equatorial cloud complex was made possible by the Keck Visiting Scholars Program, a new program launched this summer that gives graduate students and post-doctoral researchers experience working at the telescope, while contributing to Keck Observatory and its scientific community.

    “This result by Imke and her first year graduate student, Ned, is a perfect example of what we’re trying to accomplish with the Keck Visiting Scholars Program,” said Anne Kinney, chief scientist at Keck Observatory. “Ned is our first visiting scholar, and his incredible work is a testament to the value of this program. It’s just been an outrageous success.”

    4

    Molter (pictured above with Kinney) is one of eight scholars accepted into the program this year. His assignment during his six-week stay at the Observatory was to develop a more efficient method for twilight observing, making use of time that otherwise might not be used. Most observers in the Keck Observatory community peer deep into the night sky and cannot observe their targets during the ‘Twilight Zone.’

    “Ned had never observed before, and he’s very bright, so when Anne told me about the program, I knew he would be the perfect student for it,” said de Pater. “Now that we’ve discovered this interesting cloud complex in Neptune, Ned has a running start on a nice paper for his PhD thesis.”

    “I loved being at Keck. Everyone was extremely friendly and I had a ton of personal interaction with the support astronomers and observing assistants,” said Molter. Being able to go behind the scenes to see how they run the telescopes and instruments every day, getting 10 nights of observing and engineering time on the telescopes, and going up to the summit twice to see the incredible engineering behind this gigantic machine has turned me from a student to an actual observer. It was an incredible opportunity.”

    The Keck Visiting Scholars Program is generously sponsored by Roy and Frances Simperman, with major contributions from the M. R. and Evelyn Hudson Foundation, William M. Keck, Jr. Foundation, Edge of Space, Inc., Thomas McIntyre, and Jeff and Rebecca Steele.

    NEXT STEPS

    Molter and De Pater will continue to analyze their data and propose for more twilight observing time at Keck Observatory this fall so they can learn more about the nature of this storm and get an idea of what it will be doing over time.

    Having a better understanding of Neptune’s atmosphere will help give astronomers a clearer picture of this icy giant’s global circulation. This has become increasingly more important in the exoplanet realm, as a majority of exoplanets found so far are nearly the size of Neptune. While scientists can calculate their size and mass, not much is currently known about exoplanets’ atmosphere.

    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 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.

    3
    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 .

    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 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.

    STEM Icon

    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: , , , , , 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

     
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