Tagged: Astronomy Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 8:11 pm on August 25, 2016 Permalink | Reply
    Tags: Astronomy, , ,   

    From JPL-Caltech: “Spitzer Space Telescope Begins ‘Beyond’ Phase” 

    NASA JPL Banner

    JPL-Caltech

    NASA Spitzer Telescope
    Spitzer

    August 25, 2016

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

    1

    Spitzer Space Telescope Begins ‘Beyond’ Phase

    This diagram shows how the different phases of Spitzer’s mission relate to its location relative to the Earth over time.Credit: NASA/JPL-Caltech

    Celebrating the spacecraft’s ability to push the boundaries of space science and technology, NASA’s Spitzer Space Telescope team has dubbed the next phase of its journey “Beyond.”

    “Spitzer is operating well beyond the limits that were set for it at the beginning of the mission,” said Michael Werner, the project scientist for Spitzer at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We never envisioned operating 13 years after launch, and scientists are making discoveries in areas of science we never imagined exploring with the spacecraft.”

    NASA recently granted the spacecraft a two-and-a-half-year mission extension. This Beyond phase of the Spitzer mission will explore a wide range of topics in astronomy and cosmology, as well as planetary bodies in and out of our solar system.

    Because of Spitzer’s orbit and age, the Beyond phase presents a variety of new engineering challenges. Spitzer trails Earth in its journey around the sun, but because the spacecraft travels slower than Earth, the distance between Spitzer and Earth has widened over time. As Spitzer gets farther away, its antenna must be pointed at higher angles toward the sun to communicate with Earth, which means that parts of the spacecraft will experience more and more heat. At the same time, Spitzer’s solar panels point away from the sun and will receive less sunlight, so the batteries will be under greater stress. To enable this riskier mode of operations, the mission team will have to override some autonomous safety systems.

    “Balancing these concerns on a heat-sensitive spacecraft will be a delicate dance, but engineers are hard at work preparing for the new challenges in the Beyond phase,” said Mark Effertz, the Spitzer spacecraft chief engineer at Lockheed Martin Space Systems Company, Littleton, Colorado, which built the spacecraft.

    Spitzer, which launched on Aug. 25, 2003, has consistently adapted to new scientific and engineering challenges during its mission, and the team expects it will continue to do so during the “Beyond” phase, which begins Oct. 1. The selected research proposals for the Beyond phase, also known as Cycle 13, include a variety of objects that Spitzer wasn’t originally planned to address — such as galaxies in the early universe, the black hole at the center of the Milky Way and exoplanets.

    Sag A*  NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole 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

    “We never even considered using Spitzer for studying exoplanets when it launched,” said Sean Carey of NASA’s Spitzer Science Center at Caltech in Pasadena. “It would have seemed ludicrous back then, but now it’s an important part of what Spitzer does.”

    Spitzer’s exoplanet exploration

    Spitzer has many qualities that make it a valuable asset in exoplanet science, including an extremely accurate star-targeting system and the ability to control unwanted changes in temperature. Its stable environment and ability to observe stars for long periods of time led to the first detection of light from known exoplanets in 2005. More recently, Spitzer’s Infrared Array Camera (IRAC) has been used for finding exoplanets using the “transit” method — looking for a dip in a star’s brightness that corresponds to a planet passing in front of it. This brightness change needs to be measured with exquisite accuracy to detect exoplanets. IRAC scientists have created a special type of observation to make such measurements, using single pixels within the camera.

    Another planet-finding technique that Spitzer uses, but was not designed for, is called microlensing. When a star passes in front of another star, the gravity of the first star can act as a lens, making the light from the more distant star appear brighter. Scientists are using microlensing to look for a blip in that brightening, which could mean that the foreground star has a planet orbiting it. Spitzer and the ground-based Polish Optical Gravitational Lensing Experiment (OGLE) were used together to find one of the most distant planets known outside the solar system, as reported in 2015. This type of investigation is made possible by Spitzer’s increasing distance from Earth, and could not have been done early in the mission.

    Peering into the early universe

    Understanding the early universe is another area where Spitzer has broken ground. IRAC was designed to detect remote galaxies roughly 12 billion light-years away — so distant that their light has been traveling for roughly 88 percent of the history of the universe. But now, thanks to collaborations between Spitzer and NASA’s Hubble Space Telescope, scientists can peer even further into the past. The farthest galaxy ever seen, GN-z11, was characterized in a 2016 study using data from these telescopes. GN-z11 is about 13.4 billion light-years away, meaning its light has been traveling since 400 million years after the big bang.

    “When we designed the IRAC instrument, we didn’t know those more distant galaxies existed,” said Giovanni Fazio, principal investigator of IRAC, based at the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts. “The combination of the Hubble Space Telescope and Spitzer has been fantastic, with the telescopes working together to determine their distance, stellar mass and age.”

    Closer to home, Spitzer advanced astronomers’ understanding of Saturn when scientists using the observatory discovered the planet’s largest ring in 2009. Most of the material in this ring — consisting of ice and dust — begins 3.7 million miles (6 million kilometers) from Saturn and extends about 7.4 million miles (12 million kilometers) beyond that. Though the ring doesn’t reflect much visible light, making it difficult for Earth-based telescopes to see, Spitzer could detect the infrared glow from the cool dust.

    The multiple phases of Spitzer

    Spitzer reinvented itself in May 2009 with its warm mission, after the depletion of the liquid helium coolant that was chilling its instruments since August 2003. At the conclusion of the “cold mission,” Spitzer’s Infrared Spectrograph and Multiband Imaging Photometer stopped working, but two of the four cameras in IRAC persisted. Since then, the spacecraft has made numerous discoveries despite operating in warmer conditions (which, at about minus 405 Fahrenheit or 30 Kelvin, is still cold by Earthly standards).

    “With the IRAC team and the Spitzer Science Center team working together, we’ve really learned how to operate the IRAC instrument better than we thought we could,” Fazio said. “The telescope is also very stable and in an excellent orbit for observing a large part of the sky.”

    Spitzer’s Beyond mission phase will last until the commissioning phase of NASA’s James Webb Space Telescope, currently planned to launch in October 2018. Spitzer is set to identify targets that Webb can later observe more intensely.

    “We are very excited to continue Spitzer in its Beyond phase. We fully expect new, exciting discoveries to be made over the next two-and-a-half years,” said Suzanne Dodd, project manager for Spitzer, based at JPL.

    JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit:

    http://spitzer.caltech.edu

    http://www.nasa.gov/spitzer

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

    Caltech Logo

    jpl

    NASA image

     
  • richardmitnick 2:50 pm on August 25, 2016 Permalink | Reply
    Tags: Astronomy, , , , ,   

    From JHU: “Can one cosmic enigma help solve another? Johns Hopkins researchers think so” 

    Johns Hopkins
    Johns Hopkins University

    8.24.16
    Arthur Hirsch

    1
    Image credit: VectaRay

    2
    A massive cluster of yellowish galaxies, seemingly caught in a red and blue spider web of eerily distorted background galaxies, makes for a spellbinding picture from the new Advanced Camera for Surveys aboard NASA’s Hubble Space Telescope. To make this unprecedented image of the cosmos, Hubble peered straight through the center of one of the most massive galaxy clusters known, called Abell 1689. The gravity of the cluster’s trillion stars — plus dark matter — acts as a 2-million-light-year-wide lens in space. This gravitational lens bends and magnifies the light of the galaxies located far behind it. Some of the faintest objects in the picture are probably over 13 billion light-years away (redshift value 6). Strong gravitational lensing as observed by the Hubble Space Telescope in Abell 1689 indicates the presence of dark matter. Credit: NASA, N. Benitez (JHU), T. Broadhurst (Racah Institute of Physics/The Hebrew University), H. Ford (JHU), M. Clampin (STScI),G. Hartig (STScI), G. Illingworth (UCO/Lick Observatory), the ACS Science Team and ESA. phys.org.

    Astrophysicists from Johns Hopkins University have proposed a clever new way of shedding light on the mysterious dark matter believed to make up most of the universe. The irony is they want to try to pin down the nature of this unexplained phenomenon by using another obscure cosmic emanation known as “fast radio bursts.”

    In a paper published today in Physical Review Letters, the team of astrophysicists argues that these extremely bright and brief flashes of radio-frequency radiation can provide clues about whether certain black holes are dark matter.

    Julian Muñoz, a Johns Hopkins graduate student and the paper’s lead author, said fast radio bursts, or FRBs, provide a direct and specific way of detecting black holes of a specific mass, which are the suspect dark matter.

    FRB Fast Radio Bursts from NAOJ Subaru
    FRB Fast Radio Bursts from NAOJ Subaru, Mauna Key, Hawaii, USA

    Muñoz wrote the paper along with Ely D. Kovetz, a post-doctoral fellow; Marc Kamionkowski, a professor in the Department of Physics and Astronomy; and Liang Dai, who completed his doctorate in astrophysics at Johns Hopkins last year. Dai is now a NASA Einstein Postdoctoral Fellow at the Institute for Advanced Study in Princeton, New Jersey.

    The paper builds on a hypothesis offered in a paper published this spring by Muñoz, Kovetz, and Kamionkowski, along with five Johns Hopkins colleagues. Also published in Physical Review Letters, that research made a speculative case that the collision of black holes detected early in the year by the Laser Interferometer Gravitational-Wave Observatory, or LIGO, was actually dark matter, a substance that makes up 85 percent of the mass of the universe.

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib
    Credit: MPI for Gravitational Physics/W.Benger-Zib
    LSC LIGO Scientific Collaboration
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    The earlier paper made what Kamionkowski called a “plausibility argument” that LIGO found dark matter. The study took as a point of departure the fact that the objects detected by LIGO fit within the predicted range of mass of so-called “primordial” black holes. Unlike black holes that formed from imploded stars, primordial black holes are believed to have formed from the collapse of large expanses of gas during the birth of the universe.

    The existence of primordial black holes has not been established with certainty, but they have been suggested before as a possible solution to the riddle of dark matter. With so little evidence of them to examine, the hypothesis had not gained a large following among scientists.

    The earlier paper made what Kamionkowski called a “plausibility argument” that LIGO found dark matter. The study took as a point of departure the fact that the objects detected by LIGO fit within the predicted range of mass of so-called “primordial” black holes. Unlike black holes that formed from imploded stars, primordial black holes are believed to have formed from the collapse of large expanses of gas during the birth of the universe.

    The LIGO findings, however, raised the prospect anew, especially as the objects detected in that experiment conform to the mass predicted for dark matter.

    The Johns Hopkins team calculated how often these primordial black holes would form binary pairs, and eventually collide. Taking into account the size and elongated shape believed to characterize primordial black hole binary orbits, the team came up with a collision rate that conforms to the LIGO findings.

    Key to the argument is that the black holes that LIGO detected fall within a range of 29 to 36 solar masses, meaning they are that many times greater than the mass of the sun. The new paper considers the question of how to test the hypothesis that dark matter consists of black holes of roughly 30 solar masses.

    That’s where the fast radio bursts come in. First observed only a few years ago, these flashes of radio frequency radiation emit intense energy, but last only fractions of a second. Their origins are unknown but are believed to lie in galaxies outside the Milky Way.

    If the speculation about their origins is true, Kamionkowski said, the radio waves would travel great distances before they’re observed on Earth, perhaps passing a black hole. According to Einstein’s theory of general relativity, the ray would be deflected when it passes a black hole. If it passes close enough, it could be split into two rays shooting off in the same direction—creating two images from one source.

    The new study shows that if the black hole has 30 times the mass of the Sun, the two images will arrive a few milliseconds apart. If 30-solar-mass black holes make up the dark matter, there is a chance that any given fast radio burst will be deflected in this way and followed in a few milliseconds by an echo.

    “The echoing of FRBs is a very direct probe of dark matter,” Muñoz said. “While gravitational waves might ‘indicate’ that dark matter is made of black holes, there are other ways to produce very-massive black holes with regular astrophysics, so it would be hard to convince oneself that we are detecting dark matter. However, gravitational lensing of fast radio bursts has a very unique signature, with no other astrophysical phenomenon that could reproduce it.”

    Kaimonkowski said that while the probability for any such FRB echo is small, “it is expected that several of the thousands of FRBs to be detected in the next few years will have such echoes … if black holes make up the dark matter.”

    So far, only about 20 fast radio bursts have been detected and recorded since 2001. The very sensitive instruments needed to detect them can look at only very small slices of the sky at a time, limiting the rate at which the bursts can be found. A new telescope expected to go into operation this year that seems particularly promising for spotting radio bursts is the Canadian Hydrogen Intensity Mapping Experiment. The joint project of the University of British Columbia, McGill University, the University of Toronto, and the Dominion Radio Astrophysical Observatory stands in British Columbia.

    “Once the thing is working up to their planned specifications, they should collect enough FRBs to begin the tests we propose,” said Kamionkowski, estimating results could be available in three to five years.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    Johns Hopkins Campus

    The Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

    The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

    What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

     
  • richardmitnick 1:57 pm on August 25, 2016 Permalink | Reply
    Tags: Astronomy, , Dark galaxy Dragonfly 44, , , ,   

    From Keck: “Scientists Discover Massive Galaxy Made of 99.99 Percent Dark Matter” 

    Keck Observatory

    August 25, 2016

    SCIENCE CONTACT
    Pieter van Dokkum
    Yale University
    New Haven, Connecticut, USA
    Tel: +1-203-432-3000
    E-mail: pieter.vandokkum@yale.edu

    MEDIA CONTACT

    Steve Jefferson
    W. M. Keck Observatory
    (808) 881-3827
    sjefferson@keck.hawaii.edu

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

    Keck Observatory

    1
    The dark galaxy Dragonfly 44. The image on the left is a wide view of the galaxy taken with the Gemini North telescope using the Gemini Multi-Object Spectrograph (GMOS). The close-up on the right is from the same very deep image, revealing the large, elongated galaxy, and halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy. Dragonfly 44 is very faint for its mass, and consists almost entirely of Dark Matter. Credit: Pieter van Dokkum, Roberto Abraham, Gemini; Sloan Digital Sky Survey.

    Using the world’s most powerful telescopes, an international team of astronomers has discovered a massive galaxy that consists almost entirely of Dark Matter. Using the W. M. Keck Observatory and the Gemini North telescope – both on Maunakea, Hawaii – the team found a galaxy whose mass is almost entirely Dark Matter. The findings are being published in The Astrophysical Journal Letters today.

    Gemini/North telescope at Manua Kea, Hawaii, USA
    GEMINI/North GMOS
    Gemini/North telescope at Manua Kea, Hawaii, USA; GEMINI/North GMOS

    Even though it is relatively nearby, the galaxy, named Dragonfly 44, had been missed by astronomers for decades because it is very dim. It was discovered just last year when the Dragonfly Telephoto Array observed a region of the sky in the constellation Coma.

    U Toronto Dunlap Dragonfly telescope Array
    U Toronto Dunlap Dragonfly telescope Array

    Upon further scrutiny, the team realized the galaxy had to have more than meets the eye: it has so few stars that it quickly would be ripped apart unless something was holding it together.

    To determine the amount of Dark Matter in Dragonfly 44, astronomers used the DEIMOS instrument installed on Keck II to measure the velocities of stars for 33.5 hours over a period of six nights so they could determine the galaxy’s mass.

    Keck/DEIMOS
    Keck/DEIMOS

    The team then used the Gemini Multi-Object Spectrograph (GMOS) on the 8-meter Gemini North telescope on Maunakea in Hawaii to reveal a halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy.

    “Motions of the stars tell you how much matter there is, van Dokkum said. “They don’t care what form the matter is, they just tell you that it’s there. In the Dragonfly galaxy stars move very fast. So there was a huge discrepancy: using Keck Observatory, we found many times more mass indicated by the motions of the stars, then there is mass in the stars themselves.”

    The mass of the galaxy is estimated to be a trillion times the mass of the Sun – very similar to the mass of our own Milky Way galaxy. However, only one hundredth of one percent of that is in the form of stars and “normal” matter; the other 99.99 percent is in the form of dark matter. The Milky Way has more than a hundred times more stars than Dragonfly 44.

    Finding a galaxy with the mass of the Milky Way that is almost entirely dark was unexpected. “We have no idea how galaxies like Dragonfly 44 could have formed,” Roberto Abraham, a co-author of the study, said. “The Gemini data show that a relatively large fraction of the stars is in the form of very compact clusters, and that is probably an important clue. But at the moment we’re just guessing.”

    “This has big implications for the study of Dark Matter,” van Dokkum said. “It helps to have objects that are almost entirely made of Dark Matter so we don’t get confused by stars and all the other things that galaxies have. The only such galaxies we had to study before were tiny. This finding opens up a whole new class of massive objects that we can study.

    “Ultimately what we really want to learn is what Dark Matter is,” van Dokkum said. “The race is on to find massive dark galaxies that are even closer to us than Dragonfly 44, so we can look for feeble signals that may reveal a Dark Matter particle.”

    Additional co-authors are Shany Danieli, Allison Merritt, and Lamiya Mowla of Yale, Jean Brodie of the University of California Observatories, Charlie Conroy of Harvard, Aaron Romanowsky of San Jose State University, and Jielai Zhang of the University of Toronto.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    DEIMOS (DEep Imaging Multi-Object Spetrograph) boasts the largest field of view (16.7 arcmin by 5 arcmin) of any of the Keck Observatory instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.

    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

    Keck NASA

    Keck Caltech

     
  • richardmitnick 1:19 pm on August 25, 2016 Permalink | Reply
    Tags: , ALMA Finds Unexpected Trove of Gas Around Larger Stars, Astronomy, , ,   

    From ALMA: “ALMA Finds Unexpected Trove of Gas Around Larger Stars” 

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

    25 August 2016
    Contacts

    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Artist impression of a debris disk surrounding a star in the Scorpius-Centaurus Association. ALMA discovered that — contrary to expectations — the more massive stars in this region retain considerable stores of carbon monoxide gas. This finding could offer new insights into the timeline for giant planet formation around young stars. Credit: NRAO/AUI/NSF; D. Berry / SkyWorks

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) surveyed dozens of young stars – some Sun-like and others nearly double that size – and discovered that the larger variety have surprisingly rich reservoirs of carbon monoxide gas in their debris disks. In contrast, the lower-mass, Sun-like stars have debris disks that are virtually gas-free.

    This finding runs counter to astronomer’s expectations, which hold that stronger radiation from larger stars should strip away gas from their debris disks faster than the comparatively mild radiation from smaller stars. It may also offer new insights into the timeline for giant planet formation around young stars.

    Debris disks are found around stars that have shed their dusty, gas-filled protoplanetary disks and gone on to form planets, asteroids, comets, and other planetesimals. Around younger stars, however, many of these newly formed objects have yet to settle into stately orbits and routinely collide, producing enough rubble to spawn a “second-generation” disk of debris.

    “Previous spectroscopic measurements of debris disks revealed that certain ones had an unexpected chemical signature suggesting they had an overabundance of carbon monoxide gas,” said Jesse Lieman-Sifry, lead author on a paper published in Astrophysical Journal. At the time of the observations, Lieman-Sifry was an undergraduate astronomy major at Wesleyan University in Middletown, Connecticut. “This discovery was puzzling since astronomers believe that this gas should be long gone by the time we see evidence of a debris disk,” he said.

    In search of clues as to why certain stars harbor gas-rich disks, Lieman-Sifry and his team surveyed 24 star systems in the Scorpius-Centaurus Association. This loose stellar agglomeration, which lies a few hundred light-years from Earth, contains hundreds of low- and intermediate-mass stars. For reference, astronomers consider our Sun to be a low-mass star.

    The astronomers narrowed their search to stars between five and ten million years old — old enough to host full-fledged planetary systems and debris disks — and used ALMA to examine the millimeter-wavelength “glow” from the carbon monoxide in the star’s debris disks.

    The team carried out their survey over a total of six nights between December 2013 and December 2014, observing for a mere ten minutes each night. At the time it was conducted, this study constituted the most extensive millimeter-wavelength interferometric survey of stellar debris disks ever achieved.

    2
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system, drawn in for scale. The location of the central star is also highlighted for reference. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    Armed with an incredibly rich set of observations, the astronomers found the most gas-rich disks ever recorded in a single study. Among their sample of two dozen disks, the researchers spotted three that exhibited strong carbon monoxide emission. Much to their surprise, all three gas-rich disks surrounded stars about twice as massive as the Sun. None of the 16 smaller, Sun-like stars in the sample appeared to have disks with large stores of carbon monoxide. These observations suggest that larger stars are more likely to sport disks with significant gas reservoirs than Sun-like stars.

    This finding is counterintuitive, because higher-mass stars flood their planetary systems with energetic ultraviolet radiation that should destroy the carbon monoxide gas lingering in their debris disks. This new research reveals, however, that the larger stars are somehow able to either preserve or replenish their carbon monoxide stockpiles.

    “We’re not sure whether these stars are holding onto reservoirs of gas much longer than expected, or whether there’s a sort of ‘last gasp’ of second-generation gas produced by collisions of comets or evaporation from the icy mantles of dust grains,” said Meredith Hughes, an astronomer at Wesleyan University and coauthor of the study.

    The existence of this gas may have important implications for planet formation, says Hughes. Carbon monoxide is a major constituent of the atmospheres of giant planets. Its presence in debris disks could mean that other gases, including hydrogen, are present, but perhaps in much lower concentrations. If certain debris disks are able to hold onto appreciable amounts of gas, it might push back the expected deadline for giant planet formation around young stars, the astronomers speculate.

    3
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    “Future high-resolution observations of these gas-rich systems may allow astronomers to infer the location of the gas within the disk, which may shed light on the origin of the gas,” says Antonio Hales, an astronomer with the Joint ALMA Observatory in Santiago, Chile, and the National Radio Astronomy Observatory in Charlottesville, Virginia, and coauthor on the study. “For instance, if the gas was produced by planetesimal collisions, it should be more highly concentrated in regions of the disk where those impacts occurred. ALMA is the only instrument capable of making these kind of high-resolution images.”

    According to Lieman-Sifry, these dusty disks are just as diverse as the planetary systems they accompany. The discovery that the debris disks around some larger stars retain carbon monoxide longer than their Sun-like counterparts may provide insights into the role this gas plays in the development of planetary systems.

    4
    Four out of 24 debris disks observed by ALMA in the Scorpius-Centaurus Association. Researchers were surprised to discover that the larger, more energetic stars retained much more gas in their debris disks than smaller, Sun-like stars. Credit: Lieman-Sifry et al. ALMA (ESO/NAOJ/NRAO); B. Saxton, NRAO/AUI/NSF

    Additional information

    This research is presented in the paper titled “Debris disks in the Scorpius-Centaurus OB association resolved by ALMA,” by J. Lieman-Sifry et al., published in Astrophysical Journal on 23 August 2016. [Preprint: http://arxiv.org/abs/1606.07068.

    The team is composed of Jesse Lieman-Sifry (Wesleyan Univ., Middletown, Connecticut), A. Meredith Hughes (Wesleyan Univ., Middletown, Connecticut), John M. Carpenter (California Institute of Technology, Pasadena), Uma Gorti (SETI Institute, Mountain View, California), Antonio Hales (Joint ALMA Observatory, Santiago, Chile, and National Radio Astronomy Observatory, Charlottesville, Virginia), and Kevin M. Flaherty (Wesleyan Univ., Middletown, Connecticut).

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 3:50 pm on August 24, 2016 Permalink | Reply
    Tags: Astronomy, , , Most Distant Galaxy Clusters Ever Found   

    From Keck: “Most Distant Galaxy Clusters Ever Found” 

    Keck Observatory

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

    Keck Observatory

    August 24, 2016
    Steve Jefferson
    W. M. Keck Observatory
    (808) 881-3827
    sjefferson@keck.hawaii.edu

    1
    Massive galaxy cluster MACS J0416 seen in X-rays (blue), visible light (red, green, and blue), and radio light (pink). Credit: NASA/CXC/SAO/G.Ogrean/STScI/NRAO/AUI/NSF.

    2
    Color images of the central regions of z > 1.35 SpARCS clusters. Cluster members are marked with white squares. Credit: Nantais, et al.

    The international University of California, Riverside-led SpARCS collaboration has discovered four of the most distant clusters of galaxies ever found, as they appeared when the Universe was only four billion years old. Clusters are rare regions of the Universe consisting of hundreds of galaxies containing trillions of stars, as well as hot gas and mysterious Dark Matter. Spectroscopic observations from the W. M. Keck Observatory on Maunakea, Hawaii and the Very Large Telescope in Chile confirmed the four candidates to be massive clusters.

    ESO/VLT at Cerro Paranal, Chile
    ESO/VLT at Cerro Paranal, Chile

    This sample is now providing the best measurement yet of when and how fast galaxy clusters stop forming stars in the early Universe.

    “We looked at how the properties of galaxies in these clusters differed from galaxies found in more typical environments with fewer close neighbors,” said lead author Julie Nantais, an assistant professor at the Andres Bello University in Chile. “It has long been known that when a galaxy falls into a cluster, interactions with other cluster galaxies and with hot gas accelerate the shut off of its star formation relative to that of a similar galaxy in the field, in a process known as environmental quenching. The SpARCS team have developed new techniques using Spitzer Space Telescope infrared observations to identify hundreds of previously-undiscovered clusters of galaxies in the distant Universe.”

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    As anticipated, the team did indeed find that many more galaxies in the clusters had stopped forming stars compared to galaxies of the same mass in the field. Gillian Wilson, professor of physics and astronomy at UC Riverside, added, “Fascinatingly, however, the study found that the percentage of galaxies which had stopped forming stars in those young, distant clusters, was much lower than the percentage found in much older, nearby clusters. While it had been fully expected that the percentage of cluster galaxies which had stopped forming stars would increase as the Universe aged, this latest work quantifies the effect.”

    The paper concludes that about 30 percent of the galaxies which would normally be forming stars have been quenched in the distant clusters, compared to the much higher value of about 50 percent found in nearby clusters.

    Several possible physical processes could be responsible for causing environmental quenching. For example, the hot, harsh cluster environment might prevent the galaxy from continuing to accrete cold gas and form new stars; a process astronomers have named “starvation”. Alternatively, the quenching could be caused by interactions with other galaxies in the cluster. These galaxies might “harass” (undergo frequent, high speed, gravitationally-disturbing encounters), tidally strip (pull material from a smaller galaxy to a larger one) or merge (two or more galaxies joining together) with the first galaxy to stop its star formation.

    While the current study does not answer the question of which process is primarily responsible, it is nonetheless hugely important because it provides the most accurate measurement yet of how much environmental quenching has occurred in the early Universe. Moreover, the study provides an all-important early-Universe benchmark by which to judge upcoming predictions from competing computational numerical simulations which make different assumptions about the relative importance of the many different environmental quenching processes which have been suggested, and the timescales upon which they operate.

    The W. M. Keck Observatory findings were obtained as the result of a collaboration amongst UC faculty members Gillian Wilson (UCR) and Michael Cooper (UCI), and graduate students Andrew DeGroot (UCR) and Ryan Foltz (UCR). Other authors involved in the study are Remco van der Burg (Université Paris Diderot), Chris Lidman (Australian Astronomical Observatory), Ricardo Demarco (WUniversidad de Concepción, Chile), Allison Noble (University of Toronto, Canada) and Adam Muzzin (University of Cambridge).

    MOSFIRE (Multi-Object Spectrograph for Infrared Exploration) is a highly-efficient instrument that can take images or up to 46 simultaneous spectra. Using a sensitive state-of-the-art detector and electronics system, MOSFIRE obtains observations fainter than any other near infrared spectrograph. MOSFIRE is an excellent tool for studying complex star or galaxy fields, including distant galaxies in the early Universe, as well as star clusters in our own Galaxy. MOSFIRE was made possible by funding provided by the National Science Foundation and astronomy benefactors Gordon and Betty Moore

    Science paper:
    Stellar mass function of cluster galaxies at z ~ 1.5: evidence for reduced quenching efficiency at high redshift, Astronomy and Astrophysics, 24 August 2016

    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

    Keck NASA

    Keck Caltech

     
  • richardmitnick 12:53 pm on August 24, 2016 Permalink | Reply
    Tags: Astronomy, , , , Proxima b,   

    From ESO: “Planet Found in Habitable Zone Around Nearest Star” 

    ESO 50 Large

    European Southern Observatory

    24 August 2016
    Guillem Anglada-Escudé (Lead Scientist)
    Queen Mary University of London
    London, United Kingdom
    Tel: +44 (0)20 7882 3002
    Email: g.anglada@qmul.ac.uk

    Pedro J. Amado (Scientist)
    Instituto de Astrofísica de Andalucía – Consejo Superior de Investigaciones Cientificas (IAA/CSIC)
    Granada, Spain
    Tel: +34 958 23 06 39
    Email: pja@iaa.csic.es

    Ansgar Reiners (Scientist)
    Institut für Astrophysik, Universität Göttingen
    Göttingen, Germany
    Tel: +49 551 3913825
    Email: ansgar.reiners@phys.uni-goettingen.de

    James S. Jenkins (Scientist)
    Departamento de Astronomia, Universidad de Chile
    Santiago, Chile
    Tel: +56 (2) 2 977 1125
    Email: jjenkins@das.uchile.cl

    Michael Endl (Scientist)
    McDonald Observatory, The University of Texas at Austin
    Austin, Texas, USA
    Tel: +1 512 471 8312
    Email: mike@astro.as.utexas.edu

    Richard Hook (Coordinating Public Information Officer)
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: proxima@eso.org

    Martin Archer (Public Information Officer)
    Queen Mary University of London
    London, United Kingdom
    Tel: +44 (0) 20 7882 6963
    Email: m.archer@qmul.ac.uk

    Silbia López de Lacalle (Public Information Officer)
    Instituto de Astrofísica de Andalucía
    Granada, Spain
    Tel: +34 958 23 05 32
    Email: silbialo@iaa.es

    Romas Bielke (Public Information Officer)
    Georg August Universität Göttingen
    Göttingen, Germany
    Tel: +49 551 39-12172
    Email: Romas.Bielke@zvw.uni-goettingen.de

    Natasha Metzler (Public Information Officer)
    Carnegie Institution for Science
    Washington DC, USA
    Tel: +1 (202) 939 1142
    Email: nmetzler@carnegiescience.edu

    David Azocar (Public Information Officer)
    Departamento de Astronomia, Universidad de Chile
    Santiago, Chile
    Email: dazocar@das.uchile.cl

    Rebecca Johnson (Public Information Officer)
    McDonald Observatory, The University of Texas at Austin
    Austin, Texas, USA
    Tel: +1 512 475 6763
    Email: rjohnson@astro.as.utexas.edu

    Hugh Jones (Scientist)
    University of Hertfordshire
    Hatfield, United Kingdom
    Tel: +44 (0)1707 284426
    Email: h.r.a.jones@herts.ac.uk

    Jordan Kenny (Public Information Officer)
    University of Hertfordshire
    Hatfield, United Kingdom
    Tel: +44 1707 286476
    Cell: +44 7730318371
    Email: j.kenny@herts.ac.uk

    Yiannis Tsapras (Scientist)
    Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg
    Heidelberg, Germany
    Tel: +49 6221 54-181
    Email: ytsapras@ari.uni-heidelberg.de

    1

    Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri

    Pale Red Dot

    Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri.

    The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.

    Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.

    During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world [1]. This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet [2].

    As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world.

    Guillem Anglada-Escudé explains the background to this unique search: “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.”

    The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result. At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance [3].

    Guillem Anglada-Escudé comments on the excitement of the last few months: “I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!”

    Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis.

    2
    ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile

    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA
    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA

    Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun [4].

    Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b’s rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons.

    This discovery will be the beginning of extensive further observations, both with current instruments [5] and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    Guillem Anglada-Escudé concludes: “Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us. Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next…”

    Note: We are aware that there have been rumours regarding this discovery. These rumours have never been confirmed and have not contained any research content. Whilst the rumours are in the public domain and can be reported, the information in this release, the paper itself and the associated visuals have been provided on an embargoed basis and therefore remain strictly under embargo until 19:00 CEST on 24 August 2016. We would be grateful if any questions or concerns are addressed to us before any action is taken. We thank you for your consideration in this matter.
    Notes

    [1] Besides data from the recent Pale Red Dot campaign, the paper incorporates contributions from scientists who have been observing Proxima Centauri for many years. These include members of the original UVES/ESO M-dwarf programme (Martin Kürster and Michael Endl), and exoplanet search pioneers such as R. Paul Butler. Public observations from the HARPS/Geneva team obtained over many years were also included.

    [2] The name Pale Red Dot reflects Carl Sagan’s famous reference to the Earth as a pale blue dot. As Proxima Centauri is a red dwarf star it will bathe its orbiting planet in a pale red glow.

    [3] The detection reported today has been technically possible for the last 10 years. In fact, signals with smaller amplitudes have been detected previously. However, stars are not smooth balls of gas and Proxima Centauri is an active star. The robust detection of Proxima b has only been possible after reaching a detailed understanding of how the star changes on timescales from minutes to a decade, and monitoring its brightness with photometric telescopes.

    [4] The actual suitability of this kind of planet to support water and Earth-like life is a matter of intense but mostly theoretical debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet’s atmosphere might also slowly be evaporating or have more complex chemistry than Earth’s due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star’s life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet’s atmosphere. Similar factors apply to the planets recently found around TRAPPIST-1.

    [5] Some methods to study a planet’s atmosphere depend on it passing in front of its star and the starlight passing through the atmosphere on its way to Earth. Currently there is no evidence that Proxima b transits across the disc of its parent star, and the chances of this happening seem small, but further observations to check this possibility are in progress.

    More information

    The team is composed of Guillem Anglada-Escudé (Queen Mary University of London, London, UK), Pedro J. Amado (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), John Barnes (Open University, Milton Keynes, UK), Zaira M. Berdiñas (Instituto de Astrofísica de Andalucia – CSIC, Granada, Spain), R. Paul Butler (Carnegie Institution of Washington, Department of Terrestrial Magnetism, Washington, USA), Gavin A. L. Coleman (Queen Mary University of London, London, UK), Ignacio de la Cueva (Astroimagen, Ibiza, Spain), Stefan Dreizler (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Michael Endl (The University of Texas at Austin and McDonald Observatory, Austin, Texas, USA), Benjamin Giesers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Sandra V. Jeffers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), James S. Jenkins (Universidad de Chile, Santiago, Chile), Hugh R. A. Jones (University of Hertfordshire, Hatfield, UK), Marcin Kiraga (Warsaw University Observatory, Warsaw, Poland), Martin Kürster (Max-Planck-Institut für Astronomie, Heidelberg, Germany), María J. López-González (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), Christopher J. Marvin (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Nicolás Morales (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), Julien Morin (Laboratoire Univers et Particules de Montpellier, Université de Montpellier & CNRS, Montpellier, France), Richard P. Nelson (Queen Mary University of London, London, UK), José L. Ortiz (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), Aviv Ofir (Weizmann Institute of Science, Rehovot, Israel), Sijme-Jan Paardekooper (Queen Mary University of London, London, UK), Ansgar Reiners (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Eloy Rodriguez (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), Cristina Rodriguez-Lopez (Instituto de Astrofísica de Andalucía – CSIC, Granada, Spain), Luis F. Sarmiento (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), John P. Strachan (Queen Mary University of London, London, UK), Yiannis Tsapras (Astronomisches Rechen-Institut, Heidelberg, Germany), Mikko Tuomi (University of Hertfordshire, Hatfield, UK) and Mathias Zechmeister (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany).

    Links

    Research paper in Nature
    Two new papers on Habitability on Proxima b

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

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

    ESO LaSilla
    LaSilla

    ESO VLT
    VLT

    ESO Vista Telescope
    VISTA

    ESO NTT
    NTT

    ESO VLT Survey telescope
    VLT Survey Telescope

    ALMA Array
    ALMA

    ESO E-ELT
    E-ELT

    ESO APEX
    Atacama Pathfinder Experiment (APEX) Telescope

     
  • richardmitnick 12:17 pm on August 24, 2016 Permalink | Reply
    Tags: Astronomers identify a young heavyweight star in the Milky Way, Astronomy, ,   

    From U Cambridge: “Astronomers identify a young heavyweight star in the Milky Way” 

    U Cambridge bloc

    Cambridge University

    22 Aug 2016
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    A young star over 30 times more massive than the Sun could help us understand how the most extreme stars in the Universe are born.
    Credit: A. Smith, Institute of Astronomy, Cambridge

    Astronomers have identified a young star, located almost 11,000 light years away, which could help us understand how the most massive stars in the Universe are formed. This young star, already more than 30 times the mass of our Sun, is still in the process of gathering material from its parent molecular cloud, and may be even more massive when it finally reaches adulthood.

    The researchers, led by a team at the University of Cambridge, have identified a key stage in the birth of a very massive star, and found that these stars form in a similar way to much smaller stars like our Sun – from a rotating disc of gas and dust. The results will be presented this week at the Star Formation 2016 conference at the University of Exeter, and are reported in the Monthly Notices of the Royal Astronomical Society.

    In our galaxy, massive young stars – those with a mass at least eight times greater than the Sun – are much more difficult to study than smaller stars. This is because they live fast and die young, making them rare among the 100 billion stars in the Milky Way, and on average, they are much further away.

    “An average star like our Sun is formed over a few million years, whereas massive stars are formed orders of magnitude faster — around 100,000 years,” said Dr John Ilee from Cambridge’s Institute of Astronomy, the study’s lead author. “These massive stars also burn through their fuel much more quickly, so they have shorter overall lifespans, making them harder to catch when they are infants.”

    The protostar that Ilee and his colleagues identified resides in an infrared dark cloud – a very cold and dense region of space which makes for an ideal stellar nursery. However, this rich star-forming region is difficult to observe using conventional telescopes, since the young stars are surrounded by a thick, opaque cloud of gas and dust. But by using the Submillimeter Array (SMA) in Hawaii and the Karl G Jansky Very Large Array (VLA) in New Mexico, both of which use relatively long wavelengths of light to observe the sky, the researchers were able to ‘see’ through the cloud and into the stellar nursery itself.

    CfA Submillimeter Array Hawaii SAO
    CfA Submillimeter Array Hawaii SAO

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA
    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    By measuring the amount of radiation emitted by cold dust near the star, and by using unique fingerprints of various different molecules in the gas, the researchers were able to determine the presence of a ‘Keplerian’ disc – one which rotates more quickly at its centre than at its edge.

    “This type of rotation is also seen in the Solar System – the inner planets rotate around the Sun more quickly than the outer planets,” said Ilee. “It’s exciting to find such a disc around a massive young star, because it suggests that massive stars form in a similar way to lower mass stars, like our Sun.”

    The initial phases of this work were part of an undergraduate summer research project at the University of St Andrews, funded by the Royal Astronomical Society (RAS). The undergraduate carrying out the work, Pooneh Nazari, said, “My project involved an initial exploration of the observations, and writing a piece of software to ‘weigh’ the central star. I’m very grateful to the RAS for providing me with funding for the summer project — I’d encourage anyone interested in academic research to try one!”

    From these observations, the team measured the mass of the protostar to be over 30 times the mass of the Sun. In addition, the disc surrounding the young star was also calculated to be relatively massive, between two and three times the mass of our Sun. Dr Duncan Forgan, also from St Andrews and lead author of a companion paper, said, “Our theoretical calculations suggest that the disc could in fact be hiding even more mass under layers of gas and dust. The disc may even be so massive that it can break up under its own gravity, forming a series of less massive companion protostars.”

    The next step for the researchers will be to observe the region with the Atacama Large Millimetre Array (ALMA), located in Chile. This powerful instrument will allow any potential companions to be seen, and allow researchers to learn more about this intriguing young heavyweight in our galaxy.

    This work has been supported by a grant from the European Research Council.

    References:
    J.D. Ilee et al. ‘G11.92-0361 MM1: A Keplerian disc around a massive young proto O-star. Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1912

    D. H. Forgan et al. Self-gravitating disc candidates around massive young stars. Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1917

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 9:39 am on August 24, 2016 Permalink | Reply
    Tags: , , Astronomy, ,   

    From AAO: “4MOST — 4-metre Multi-Object Spectroscopic Telescope” 

    AAO Australian Astronomical Observatory

    Australian Astronomical Observatory

    The Instrumentation Group at the AAO is developing the AESOP instrument for a major international consortium called 4MOST, for the European Southern Observatory (ESO). The AESOP positioner is based on the AAO’s patented ‘Echidna’ fibre-positioning technology, which has been deployed at Japan’s 8-m Subaru telescope in Hawai’i.

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA
    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    Because the AAO is providing a critical technology that cannot be sourced elsewhere, Australia is the only one of the 13 international partners in this consortium that is not an ESO member.

    4MOST will upgrade the 4-m VISTA telescope in Chile with a revolutionary, massively multiplexed spectroscopic capability and is intended to complement three key all­-sky, space­-based ob­servatories: Gaia, EUCLID, and eROSITA.

    In addition to several European-led surveys, Simon Driver of UWA will lead the WAVES survey with 4MOST: a 2 million galaxy survey designed to unlock some of the mysteries of dark matter and galaxy formation.

    https://www.4most.eu/

    1
    The 4MOST consortium has been selected by the European Southern Observatory (ESO) to provide the ESO community with a fibre-fed spectroscopic survey facility on the VISTA telescope with a large enough field-of-view to survey a large frac­tion of the southern sky in a few years.

    ESO/Vista Telescope
    ESO/Vista Telescope

    The facility will be able to simultaneously obtain spectra of ~2400 objects distributed over an hexagonal field-of-view of 4 square degrees. This high multiplex of 4MOST, combined with its high spectral resolution, will enable detection of chemical and kinematic substructure in the stellar halo, bulge and thin and thick discs of the Milky Way, thus help unravel the origin of our home galaxy. The instrument will also have enough wavelength coverage to secure velocities of extra-galactic objects over a large range in red­shift, thus enabling measurements of the evolution of galaxies and the structure of the cosmos.

    This exceptional instrument enables many science goals, but the design is especially intended to complement three key all­-sky, space­-based ob­servatories of prime European interest: Gaia, EUCLID, and eROSITA.

    ESA/Gaia satellite
    ESA/Gaia satellite

    ESA/Euclid spacecraft
    ESA/Euclid spacecraft

    3
    eROSITA

    Such a facility has been identified as of critical importance in a number of recent European strategic documents (Bode et al., 2008; de Zeeuw & Molster, 2007; Drew et al., 2010; Turon et al., 2008) and forms the perfect com­plement to the many all­-sky survey pro­jects around the world.

    4MOST is currently in its Preliminary Design Phase with an expected start of science operations in 2021.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    AAO Anglo Australian Telescope Exterior
    AAO Anglo Australian Telescope Interior
    Anglo-Australian telescope

    The Australian Astronomical Observatory, a division of the Department of Industry, Innovation and Science, operates the Anglo-Australian and UK Schmidt telescopes on behalf of the astronomical community of Australia. To this end the Observatory is part of and is funded by the Australian Government. Its function is to provide world-class observing facilities for Australian optical astronomers.

     
  • richardmitnick 8:12 am on August 24, 2016 Permalink | Reply
    Tags: Astronomy, ,   

    From NRAO: “Record Demand for ALMA in Cycle 4 Call for Proposals” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    23 August 2016
    Charles Blue
    NRAO Public Information Officer
    +1 434.296.0314;
    cblue@nrao.edu

    The international partners in the Atacama Large Millimeter/submillimeter Array (ALMA) saw record demand for telescope time from the international astronomical community during ALMA’s Cycle 4 Call for Proposals. This new observing cycle begins October 2016 and continues through September 2017.

    1
    This map shows the location from which each ALMA Cycle 4 observation proposal was submitted. Credit: ALMA (NRAO/NAOJ/ESO)

    The high demand for this revolutionary telescope was reflected in a 50-percent increase in the number of hours requested during Cycle 4 compared to the previous observing cycle. For Cycle 4, more than 400 astronomers received observing time with ALMA, the most powerful telescope of its kind.

    The selection process took almost five months to complete and included experts from around the world meeting for a week in June in Vienna, Austria, to evaluate a field of 1,571 proposals. Combined, these proposals account for 18,640 hours of observing time (12,285 hours for the 12-meter Array and 6,345 hours for the Compact Array).

    2
    Breakdown of ALMA Cycle 4 accepted proposals by science category. Credit: Composition: ALMA (ESO/NAOJ/NRAO) | Background images: The Sun – ALMA (ESO/NAOJ/NRAO). CMB: NASA/WMAP Science Team, Astrochemistry: ESO/L. Calçada & NASA/JPL-Caltech/WISE Team, Centaurus A: ALMA (ESO/NAOJ/NRAO); Y. Beletsky (LCO)/ESO, HL Tau: ALMA (ESO/NAOJ/NRAO).

    At their meeting, the 145 science advisers of the ALMA Proposal Review Committee established the selection criteria and ranked each submission as objectively as possible. The selection criteria included the scientific merit of the proposal, its technical feasibility, and the likelihood of its success.

    In the end, the review committee granted 3,000 hours of observing time on the 12-meter Array and 1,800 hours on the Compact Array.

    3
    Description of ALMA Cycle 4 main new capabilities. Credit: ALMA (ESO/NAOJ/NRAO)

    The research category with the most proposals requested and selected — about one in every four — was Interstellar Medium, Star Formation and Astrochemistry. Three other categories — Cosmology and High Redshift Universe; Galaxies and Galactic Nuclei; and Circumstellar Discs, Exoplanets and the Solar System – each account for about one of every five proposals. The Stellar Evolution and the Sun category accounts for about one in ten.

    The astronomers affiliated with 476 selected proposals will have access to at least fifty-three ALMA antennas to search the Universe — forty-three 12-meter antennas and ten 7-meter antennas. Though all of ALMA’s 66 antennas are operational, ongoing maintenance and relocation limits the total number of antennas available at any given time. For the upcoming observations, the antennas will utilize seven receivers (Bands 3, 4, 6, 7, 8, 9 and 10), each probing a different region of the millimeter/submillimeter spectrum. During Cycle 4, ALMA will be able to observe with a maximum angular resolution of 0.029 arc-seconds, using a 12.6-kilometer maximum baseline.

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

    ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    ALMA Array

    NRAO ALMA
    NRAO/GBT radio telescope
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
  • richardmitnick 8:03 am on August 24, 2016 Permalink | Reply
    Tags: Astronomy, , Chinese astronomers discover a large cavity around the Tycho's supernova,   

    From phys.org: “Astronomers discover a large cavity around the Tycho’s supernova” 

    physdotorg
    phys.org

    August 23, 2016
    Tomasz Nowakowski

    1
    The large-field WISE [12–4.6] µm infrared image around the Tycho’s supernova remnant (SNR). The red circle shows the position and size of the shell-like structure in the Tycho’s SNR, while the yellow dashed ellipse shows the cavity found in the MWISP CO images. The three white dashed lines are shown to guide the eye for the stream-like structures seen in the CO images. The white arrows mark the positions of the pillar-like structures found in the WISE image. Credit: Chen et al., 2016.

    NASA/WISE Telescope
    NASA/WISE Telescope

    Chinese astronomers have detected a large cavity existing around Tycho’s supernova, also know as SN 1572, exhibiting stream-like structures. The findings, reported in a paper published Aug. 18 on arXiv.org, show that the environments of the supernovae may be much more complicated than previously thought.

    SN 1572 lies between 8,000 to 10,000 light years from the Earth in the constellation Cassiopeia. It is a well-established type Ia supernova, one of about eight supernovae visible to the naked eye in historical records. As one of the most popular supernova remnants in our galaxy, it has been widely observed in the entire electromagnetic spectrum, and astronomers have discovered a shell-like structure produced by the shocks from the explosion as well as circumstellar material and dust.

    More recent observations of Tycho’s supernova were conducted by a team of Chinese astronomers led by Xuepeng Chen of the Purple Mountain Observatory (PMO) in Nanjing, China. They used the 13.7-meter millimeter-wavelength telescope of the Qinghai station of PMO at Delingha in China to perform large-field and high-sensitivity carbon monoxide (CO) molecular line observations of SN 1572.

    2
    13.7-meter millimeter-wavelength telescope of the Qinghai station of PMO at Delingha in China

    The scientists observed the supernova from November 2011 to February 2016 as part of the Milky Way Imaging Scroll Painting (MWISP) survey, which investigates the nature of the molecular gas along the northern Galactic Plane.

    “We present large-field CO (1-0) molecular line observations toward the Tycho’s supernova remnant, using the PMO 13.7-meter telescope. Based on the CO observations, we find a large cavity with radii of 0.3 degrees by 0.6 degrees around the remnant, which is further confirmed by the complementary infrared images from the space telescopes,” the researchers wrote in the paper.

    The team estimated that the cavity is located about 8,000 light years away and has radii of 42 and 88 light years. Their calculations allowed them to estimate that this cavity is expanding at a velocity of approximately 4 km s-1.

    Moreover, the astronomers distinguished stream-like structures in the cavity that could be part of a larger cavity seen along the line of sight. They noted that these structures may also record the accretion winds from the progenitor system. Due to these uncertainties, the team calls for further observations that could illuminate the real nature of these structures.

    “In the wind-regulated accretion models, the accretion wind could last for few million years, and the white dwarf may explode as a type Ia supernova while the accretion wind is still active. Therefore, another possible explanation is that these stream-like structures actually record the accretion winds from the progenitor system. This scenario is somehow supported by the infrared observations, in which knot-like structures are also found in the southwest and west of the cavity,” the paper reads.

    The scientists also investigated the origin of the cavity. They excluded the possibility that it could be produced by bright star in the region or the option that it was randomly distributed. According to the paper, the most plausible hypothesis taken into account is that it could be explained by the accretion wind from the progenitor system of the Tycho’s supernova.

    “The discovery of the Tycho’s cavity also gives us an alert that the environments of the supernovae Ia may be much more complicated than we thought before,” the researchers concluded.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

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

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

Get every new post delivered to your Inbox.

Join 597 other followers

%d bloggers like this: