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  • richardmitnick 9:18 am on March 22, 2019 Permalink | Reply
    Tags: , , , , , , Gemini South, HP 1   

    From Gemini Observatory: “Ultra-sharp Images Make Old Stars Look Absolutely Marvelous! “ 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    March 21, 2019

    Media Contact:

    Peter Michaud
    Public Information and Outreach manager
    Gemini Observatory
    Email: pmichaud”at”gemini.edu
    Desk: 808-974-2510
    Cell: 808-936-6643

    Science Contacts:

    Leandro Kerber
    Universidade Estadual de Santa Cruz, Brazil
    Email: lokerber”at”uesc.br
    Cell: +55 11 94724-6073
    Desk: +55 73 3680-5167

    1
    Figure 1. Color composite GSAOI+GeMS image of HP 1 obtained using the Gemini South telescope in Chile. North is up and East to the left. Composite image produced by Mattia Libralato of the Space Telescope Science Institute. Credit: Gemini Observatory/AURA/NSF.

    2
    GSAOI+GeMS color composite image of HP 1 (right image) shown relative to the full field of the cluster obtained by the Visible and Infrared Survey Telescope for Astronomy (left). Credit: Gemini Observatory/NSF/AURA/VISTA/Aladin/CDS.

    Part of ESO’s Paranal Observatory, the VLT Survey Telescope (VISTA) observes the brilliantly clear skies above the Atacama Desert of Chile. It is the largest survey telescope in the world in visible light.
    Credit: ESO/Y. Beletsky, with an elevation of 2,635 metres (8,645 ft) above sea level

    Using high-resolution adaptive optics imaging from the Gemini Observatory, astronomers have uncovered one of the oldest star clusters in the Milky Way Galaxy. The remarkably sharp image looks back into the early history of our Universe and sheds new insights on how our Galaxy formed.

    Just as high-definition imaging is transforming home entertainment, it is also advancing the way astronomers study the Universe.

    “Ultra-sharp adaptive optics images from the Gemini Observatory allowed us to determine the ages of some of the oldest stars in our Galaxy,” said Leandro Kerber of the Universidade de São Paulo and Universidade Estadual de Santa Cruz, Brazil. Kerber led a large international research team that published their results in the April 2019 issue of the Monthly Notices of the Royal Astronomical Society.

    Gemini Observatory Adaptie Optics-Gemini South on the summit of Cerro Pachón in Chile (left) and Gemini North on the summit of Mauna Kea in Hawai’i, USA (right). Image credit Gemini/NSF/AURA

    Using advanced adaptive optics technology at the Gemini South telescope in Chile, the researchers zoomed in on a cluster of stars known as HP 1. “Removing our atmosphere’s distortions to starlight with adaptive optics reveals tremendous details in the objects we study,” added Kerber. “Because we captured these stars in such great detail, we were able to determine their advanced age and piece together a very compelling story.”

    That story begins just as the Universe was reaching its one-billionth birthday.

    “This star cluster is like an ancient fossil buried deep in our Galaxy’s bulge, and now we’ve been able to date it to a far-off time when the Universe was very young,” said Stefano Souza, a PhD student at the Universidade de São Paulo, Brazil, who worked with Kerber as part of the research team. The team’s results date the cluster at about 12.8 billion years, making these stars among the oldest ever found in our Galaxy. “These are also some of the oldest stars we’ve seen anywhere,” added Souza.

    “HP 1 is one of the surviving members of the fundamental building blocks that assembled our Galaxy’s inner bulge,” said Kerber. Until a few years ago, astronomers believed that the oldest globular star clusters — spherical swarms of up to a million stars — were only located in the outer parts of the Milky Way, while the younger ones resided in the innermost Galactic regions. However, Kerber’s study, as well as other recent work based on data from the Gemini Observatory and the Hubble Space Telescope (HST), have revealed that ancient star clusters are also found within the Galactic bulge and relatively close to the Galactic center.

    Globular clusters tell us much about the formation and evolution of the Milky Way. Most of these ancient and massive stellar systems are thought to have coalesced out of the primordial gas cloud that later collapsed to form the spiral disk of our Galaxy, while others appear to be the cores of dwarf galaxies consumed by our Milky Way. Of the roughly 160 globular clusters known in our Galaxy, about a quarter are located within the greatly obscured and tightly packed central bulge region of the Milky Way. This spherical mass of stars some 10,000 light years across forms the central hub of the Milky Way (the yolk if you will) which is made primarily of old stars, gas, and dust. Among the clusters within the bulge, those that are the most metal-poor (lacking in heavier elements) – which includes HP 1 – have long been suspected of being the oldest. HP 1 then is pivotal, as it serves as an excellent tracer of our Galaxy’s early chemical evolution.

    “HP 1 is playing a critical role in our understanding of how the Milky Way formed,” Kerber said. “It is helping us to bridge the gap in our understanding between our Galaxy’s past and its present.”

    Kerber and his international team used the exquisitely deep high-resolution adaptive optics images from Gemini Observatory as well as archival optical images from the HST to identify faint cluster members, which are essential for age determination. With this rich data set they confirmed that HP 1 is a fossil relic born less than a billion years after the Big Bang, when the Universe was in its infancy.

    “These results crown an effort of more than two decades with some of the world’s premier telescopes aimed at determining accurate chemical abundances with high-resolution spectroscopy,” said Beatriz Barbuy of the Universidade de São Paulo, coauthor of this paper and a world-renowned expert in this field. “These Gemini images are the best ground-based photometric data we have. They are at the same level of HST data, allowing us to recover a missing piece in our puzzle: the age of HP 1. From the existence of such old objects, we can attest to the short star formation timescale in the Galactic bulge, as well as its fast chemical enrichment.”

    To determine the cluster’s distance, the team used archival ground-based data to identify 11 RR Lyrae variable stars (a type of “standard candle” used to measure cosmic distances) within HP 1. The observed brightness of these RR Lyrae stars indicate that HP 1 is at a distance of about 21,500 light years, placing it approximately 6,000 light years from the Galactic center, well within the Galaxy’s central bulge region.

    Kerber and his team also used the Gemini data, as well HST, Very Large Telescope, and Gaia mission data, to refine the orbit of HP 1 within our Galaxy. This analysis shows that during HP 1’s history, the cluster came as close as about 400 light years from the Galactic center – less than one-tenth of its current distance.

    NASA/ESA Hubble Telescope

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    ESA/GAIA satellite

    “The combination of high angular resolution and near-infrared sensitivity makes GeMS/GSAOI an extremely powerful tool for studying these compact, highly dust-enshrouded stellar clusters,” added Mattia Libralato of the Space Telescope Science Institute, a coauthor on the study. “Careful characterization of these ancient systems, as we’ve done here, is paramount to refine our knowledge of our Galaxy’s formation.”

    Chris Davis, Program Officer at the National Science Foundation (NSF) for Gemini, commented, “These fabulous results demonstrate why the development of wide-field, high-resolution imaging at Gemini is key to the Observatory’s future. The recent NSF award to support the development of a similar system at Gemini North will make routine super-sharp imaging from both hemispheres a reality. These are certainly exciting times for the Observatory.”

    The Gemini observations resolve stars to about 0.1 arcsecond which is one 36 thousandths of a degree and comparable to separating two automobile headlamps from approximately 1,500 miles, or 2,500 kilometers, away (the distance from Manaus to Sao Paulo in Brazil, or from San Francisco to Dallas in the USA). This resolution was obtained using the Gemini South Adaptive Optics Imager (GSAOI) – a near-infrared adaptive optics camera used with the Gemini Multi-conjugate adaptive optics System (GeMS). GeMS is an advanced adaptive optics system utilizing three deformable mirrors to correct for distortions imparted on starlight by turbulence in layers of our atmosphere.

    See the full article here .


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    NOAO Gemini North on MaunaKea, Hawaii, USA, Altitude 4,213 m (13,822 ft)

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 2:56 pm on September 21, 2018 Permalink | Reply
    Tags: , , , , , Gemini South, GeMS “SERVS” Up Sharp Views of Young Galaxies in Early Universe, GeMS-Gemini Multi-Conjugate Adaptive Optics System, GSAOI-Gemini South Adaptive Optics Imager   

    From Gemini Observatory: “GeMS “SERVS” Up Sharp Views of Young Galaxies in Early Universe” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    1
    GeMS/GSAOI K-band image of one of the three fields targeted from the Spitzer Extragalactic Representative Volume Survey. The insets show detailed views of several distant galaxies in this field.

    Multi-conjugate adaptive optics technology at Gemini South reveals that young galaxies, with large amounts of star formation, and actively growing central black holes, were relatively compact in the early Universe.

    Gemini South Adaptive Objects laser guide star

    A team of astronomers led by Dr. Mark Lacy (National Radio Astronomy Observatory, USA) used advanced adaptive optics on the Gemini South telescope in Chile to obtain high-resolution near-infrared images of three fields from the Spitzer Extragalactic Representative Volume Survey (SERVS). Their sample includes several ultra-luminous infrared galaxies (ULIRGs) which the Herschel Space Observatory found to be undergoing large bursts of star formation within the first few billion years of the Big Bang.

    ESA/Herschel spacecraft active from 2009 to 2013

    Such galaxies have hundreds of times the infrared luminosity of a normal galaxy such as the Milky Way.

    The high-resolution GeMS images reveal that the ULIRGs have messy, irregular structures indicating that they are the product of recent galactic interactions and mergers. Lacy explains, “The fact that the disturbed morphologies of these galaxies persist into the infrared suggests that their appearance is not dominated by clumpy extinction from dust, but reflects the irregular distribution of stellar light.” Dust is highly effective at obscuring ultraviolet and blue light, but effects red and infrared light less. “These GeMS observations help reveal the physical mechanisms by which massive galaxies evolve into the objects we see today,” added Lacy.

    The team used the Gemini South Adaptive Optics Imager (GSAOI) with the Gemini Multi-Conjugate Adaptive Optics System (GeMS) to obtain K-band observations. Lacy’s team combined these Gemini data with other multiwavelength data at optical, far-infrared, and radio wavelengths to study the masses, morphologies, and star formation rates of the galaxies.

    The results of the GeMS study support previous results using the Hubble Space Telescope indicating that massive compact galaxies were more common in the early Universe than they are today.

    NASA/ESA Hubble Telescope

    The fraction of galaxies with compact structures is even higher in the GeMS data, but it is unclear whether this is due to improved resolution with GeMS or a tendency to miss the more diffuse galaxies in ground-based images that must contend with the infrared glow from the Earth’s atmosphere.

    Some of the galaxies in the study also harbor active galactic nuclei (AGN), luminous central engines powered by supermassive black holes that are actively accreting mass. The researchers found that star-forming galaxies with AGN tend to have more compact structures than ULIRGs that lack active nuclei. The team also found what appears to be a rare triple AGN system, a close grouping of three galaxies with actively growing supermassive black holes that may be headed for an imminent collision.

    “Among the sources that we examined, we have one close pair, one candidate triple black hole, and other objects with disturbed morphologies that might be late-stage mergers,” said Lacy. “Observations such as theses can therefore significantly improve the constraints on galaxy and supermassive black hole merger rates.”

    In the future, the James Webb Space Telescope (JWST) will enable studies at similar angular resolution and very high sensitivity at near-infrared wavelengths of large numbers of galaxies at these early cosmic times. However, the recent delays, and anticipated high demand for JWST, means that ground-based Multi-Conjugate Adaptive Optics systems like GeMS will continue to play an important role in targeted studies of rare infrared-bright objects in the early Universe.

    This work is published in arXiv.org.

    See the full article here .


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    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 12:42 pm on April 26, 2018 Permalink | Reply
    Tags: , , , , , Gemini South, , Stellar Thief is the Surviving Companion to a Supernova   

    From NASA/ESA Hubble Telescope: “Stellar Thief is the Surviving Companion to a Supernova” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Apr 26, 2018

    Ann Jenkins
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4488
    jenkins@stsci.edu

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

    Ori Fox
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-6768
    ofox@stsci.edu

    Stuart Ryder
    Australian Astronomical Observatory, Sydney, Australia
    011-61-2-93724843
    011-61-419-970834 (cell)
    sdr@aao.gov.au

    Alex Filippenko
    University of California, Berkeley, California
    afilippenko@berkeley.edu

    1
    Companion to a Supernova is No Innocent Bystander

    In the fading afterglow of a supernova explosion, astronomers using NASA’s Hubble Space Telescope have photographed the first image of a surviving companion to a supernova. This is the most compelling evidence that some supernovas originate in double-star systems. The companion to supernova 2001ig’s progenitor star was no innocent bystander to the explosion—it siphoned off almost all of the hydrogen from the doomed star’s stellar envelope. SN 2001ig is categorized as a Type IIb stripped-envelope supernova, which is a relatively rare type of supernova in which most, but not all, of the hydrogen is gone prior to the explosion. Perhaps as many as half of all stripped-envelope supernovas have companions—the other half lose their outer envelopes via stellar winds.

    3

    Seventeen years ago, astronomers witnessed a supernova go off 40 million light-years away in the galaxy called NGC 7424, located in the southern constellation Grus, the Crane. Now, in the fading afterglow of that explosion, NASA’s Hubble has captured the first image of a surviving companion to a supernova. This picture is the most compelling evidence that some supernovas originate in double-star systems.

    “We know that the majority of massive stars are in binary pairs,” said Stuart Ryder from the Australian Astronomical Observatory (AAO) in Sydney, Australia and lead author of the study. “Many of these binary pairs will interact and transfer gas from one star to the other when their orbits bring them close together.”

    The companion to the supernova’s progenitor star was no innocent bystander to the explosion. It siphoned off almost all of the hydrogen from the doomed star’s stellar envelope, the region that transports energy from the star’s core to its atmosphere. Millions of years before the primary star went supernova, the companion’s thievery created an instability in the primary star, causing it to episodically blow off a cocoon and shells of hydrogen gas before the catastrophe.

    The supernova, called SN 2001ig, is categorized as a Type IIb stripped-envelope supernova. This type of supernova is unusual because most, but not all, of the hydrogen is gone prior to the explosion. This type of exploding star was first identified in 1987 by team member Alex Filippenko of the University of California, Berkeley.

    How stripped-envelope supernovas lose that outer envelope is not entirely clear. They were originally thought to come from single stars with very fast winds that pushed off the outer envelopes. The problem was that when astronomers started looking for the primary stars from which supernovas were spawned, they couldn’t find them for many stripped-envelope supernovas.

    “That was especially bizarre, because astronomers expected that they would be the most massive and the brightest progenitor stars,” explained team member Ori Fox of the Space Telescope Science Institute in Baltimore. “Also, the sheer number of stripped-envelope supernovas is greater than predicted.” That fact led scientists to theorize that many of the primary stars were in lower-mass binary systems, and they set out to prove it.

    Looking for a binary companion after a supernova explosion is no easy task. First, it has to be at a relatively close distance to Earth for Hubble to see such a faint star. SN 2001ig and its companion are about at that limit. Within that distance range, not many supernovas go off. Even more importantly, astronomers have to know the exact position through very precise measurements.

    In 2002, shortly after SN 2001ig exploded, scientists pinpointed the precise location of the supernova with the European Southern Observatory’s Very Large Telescope (VLT) in Cerro Paranal, Chile. In 2004, they then followed up with the Gemini South Observatory in Cerro Pachón, Chile. This observation first hinted at the presence of a surviving binary companion.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.


    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    Knowing the exact coordinates, Ryder and his team were able to focus Hubble on that location 12 years later, as the supernova’s glow faded. With Hubble’s exquisite resolution and ultraviolet capability, they were able to find and photograph the surviving companion—something only Hubble could do.

    Prior to the supernova explosion, the orbit of the two stars around each other took about a year.

    When the primary star exploded, it had far less impact on the surviving companion than might be thought. Imagine an avocado pit—representing the dense core of the companion star—embedded in a gelatin dessert—representing the star’s gaseous envelope. As a shock wave passes through, the gelatin might temporarily stretch and wobble, but the avocado pit would remain intact.

    In 2014, Fox and his team used Hubble to detect the companion of another Type IIb supernova, SN 1993J. However, they captured a spectrum, not an image. The case of SN 2001ig is the first time a surviving companion has been photographed. “We were finally able to catch the stellar thief, confirming our suspicions that one had to be there,” said Filippenko.

    Perhaps as many as half of all stripped-envelope supernovas have companions—the other half lose their outer envelopes via stellar winds. Ryder and his team have the ultimate goal of precisely determining how many supernovas with stripped envelopes have companions.

    Their next endeavor is to look at completely stripped-envelope supernovas, as opposed to SN 2001ig and SN 1993J, which were only about 90 percent stripped. These completely stripped-envelope supernovas don’t have much shock interaction with gas in the surrounding stellar environment, since their outer envelopes were lost long before the explosion. Without shock interaction, they fade much faster. This means that the team will only have to wait two or three years to look for surviving companions.

    In the future, they also hope to use the James Webb Space Telescope to continue their search.

    Added by Manu:

    4
    Evolution Envelope-Type IIb supernova Unobscured . This graphic illustrates the scenario for the processes that create a supernova envelope type IIb despoiled, in which most, but not all, of the hydrogen envelope is lost before the explosion of the primary star. The four panels show the interaction between SN 2001ig parent star, which finally exploded, and his surviving partner. 1) Two stars orbit each other and getting closer. 2) The more massive star evolves faster, swelling to become a red giant. In this last phase of life, sheds most of its hydrogen envelope in the gravitational field of his companion. As the companion extracted almost all the hydrogen from the doomed star, creates an instability in the primary star. 3) The primary star explodes in a supernova. 4) As the glow of the supernova fades, the surviving partner becomes visible to the Hubble Space Telescope. The faint supernova remnant in the lower left, continues to evolve, but in this case is too weak to be detected by Hubble.

    How supernovae surround the outer casing stripped lose is not entirely clear. Originally it thought it came from single stars with very high winds pushing the outer envelopes. The problem was that when astronomers began searching the primary star from which the supernovae were generated, they could not find in many supernovae devoid envelope.

    “That was especially strange because astronomers expected to be the biggest and brightest progenitor stars,” said team member Ori Fox Science Institute in Baltimore Space Telescope. “In addition, the large number of supernovae devoid envelope is greater than anticipated.” This led scientists to theorize that many of the primary stars in binary systems were lower mass, and prepared to try it.

    Find a binary companion after a supernova explosion is not an easy task. First, it has to be relatively close to Earth that Hubble distance to see such a faint star. SN 2001ig and his companion are at the limit. Within that range of distance, not many supernovae are triggered. More importantly, astronomers must know the exact position through very precise measurements.


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    The paper on this team’s current work was published on March 28, 2018 in The Astrophysical Journal.

    See the full article here .

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

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  • richardmitnick 3:31 pm on March 21, 2018 Permalink | Reply
    Tags: , , , , , Gemini South, IGRINS   

    From Gemini: “IGRINS — A Unique Visiting Instrument at Gemini South” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    March 21, 2018

    1
    IGRINS and Gemini team collaboration during a site visit to Gemini South (left to right: Hwihyun Kim, Brian Chinn, Kimberly Sokal, Greg Mace, and John Good). Image credit: Kimberly Sokal (UT Austin).

    The Immersion GRating INfrared Spectrometer (IGRINS) is a cross-dispersed near-infrared spectrograph with a resolving power of R=45,000 covering the H and K windows, from 1.45 to 2.5 microns, in a single exposure.

    2
    Immersion GRating INfrared Spectrometer (IGRINS)

    Gemini is supporting the instrument team with the installation and commission of IGRINS this month at Gemini South. As a Visiting Instrument, IGRINS is ideal because it features a single observing mode and contains no moving parts. We are grateful to the IGRINS team for agreeing to support observations with the help of Gemini staff for a total of 50 nights in semester 2018A. The IGRINS visit to Gemini is supported by the US National Science Foundation under grant AST-1702267 (PI: Gregory Mace, University of Texas at Austin), and by the Korean GMT Project of KASI. Further technical details are available in papers by Yuk et al. (2010), Park et al. (2014), and Mace et al. (2016).

    Gemini frequently hosts different Visiting Instruments at each telescope every semester, so remember to keep an eye on the calls for proposals!

    See the full article here .

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    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 1:36 pm on January 20, 2018 Permalink | Reply
    Tags: , , , Core-collapse Supernova Rate Problem, , , Gemini South   

    From Gemini: “Game Over for Supernovae Hide & Seek” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    January 12, 2018

    The Core-collapse Supernova Rate Problem, or the fact that we don’t see as many core-collapse supernovae as we would expect, has a solution, thanks to research using the Gemini South telescope. The research team concludes that the majority of core collapse supernovae, exploding in luminous infrared galaxies, have previously not been found due to dust obscuration and poor spatial resolution.

    1
    SN 2013if with GeMS/GSAOI, from left to right with linear scaling: Reference image (June 2015), discovery image (April 2013) and the image subtraction. SN 2013if had a projected distance from the nucleus as small as 600 light years (200 pc), which makes it the second most nuclear CCSN discovery in a LIRG to date in the optical and near-IR after SN 2010cu.

    Core-collapse supernovae are spectacular explosions that mark the violent deaths of massive stars. An international team of astronomers, led by PhD student Erik Kool of Macquarie University in Australia, used laser guide star imaging on the Gemini South telescope to study why we don’t see as many of these core-collapse supernovae as expected.

    Gemini South Laser Guide Stars

    The study began in 2015 with the Supernova UNmasked By InfraRed detection (SUNBIRD) project which has shown that dust obscuration and limited spatial resolution can explain the small number of detections to date.

    In this, the first results of the SUNBIRD project, the team discovered three core-collapse supernovae, and one possible supernova that could not be confirmed with subsequent imaging. Remarkably, these supernovae were spotted as close as 600 light years from the bright nuclear regions of these galaxies – despite being at least 150 million light years from the Earth. “Because we observed in the near-infrared, the supernovae are less affected by dust extinction compared to optical light,” said Kool.

    According to Kool the results coming from SUNBIRD reveal that their new approach provides a powerful tool for uncovering core-collapse supernova in nuclear regions of galaxies. They also conclude that this methodology is crucial in characterizing these supernova that are invisible through other means. Kool adds, “The supernova rate problem can be resolved using the unique multi-conjugate adaptive optics capability provided by Gemini, which allows us to achieve the highest spatial resolution in order to probe very close to the nuclear regions of galaxies.” This work is published in the Monthly Notices of the Royal Astronomical Society.

    See the full article here .

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    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 4:47 pm on December 19, 2017 Permalink | Reply
    Tags: , , , , , Gemini South   

    From Gemini: “The Birth of Massive Stars Around an Unlikely Galaxy” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    December 18, 2017

    Using the Gemini South telescope, researchers extracted spectra from extremely faint optical sources which they determined are nurseries of massive stars around an elliptical galaxy. Indeed, the sources were so faint that they were previously undetected and only revealed using ~4 hour exposures with the Gemini Multi-Object Spectrograph (GMOS). It is speculated that the nurseries formed as the result of a past galactic merger.

    1
    Figure 1. Gemini South spectra for six intergalactic regions around NGC 2865.

    2
    Figure 2. The red slit is the mask overlaid onto the r-band imaging. The slits are arranged in a total of 108 long slits with two short interruptions for mechanical stability of the mask. The width of each slit is 1 arcsecond.

    Using a novel observational technique, called Multi-Slit Imaging Spectroscopy (MSIS) a team, lead by Fernanda Urrutia (Universidad de La Serena and Gemini Observatory), found a new generation of star clusters around the elliptical galaxy, NGC 2865.

    “The main result of our work is that we were able to detect all the clusters of massive stars around this elliptical galaxy,” said Urrutia. “Elliptical galaxies normally don’t have enough gas to form massive stars, thus we did not expect to observe star formation inside the galaxy, much less in its surroundings.”

    The observed star-forming regions display a high quantity of heavier elements (metallicity), suggesting that these clusters were born from chemically enriched material from past generations of stars. “These high metallicities could be explained if the clusters were formed by the enriched gas coming from a merger event with at least one other spiral galaxy that formed NGC 2865,” adds Urrutia.

    “The fate of these clusters is unclear, however. We cannot discard the possibility that these objects become globular clusters in the future,” adds team member Sergio Torres-Flores from Universidad de La Serena. Globular clusters are common in halos surrounding elliptical galaxies and this work could provide a glimpse into their early evolution.

    The clusters studied, lying outside of the main galaxy, display low surface brightness in optical light and therefore can only be detected using a blind search like the MSIS technique used in this work. The six regions found by Urrutia et al. were revealed by hydrogen-alpha light emitted when surrounding gas is excited by high-energy radiation from the nearby young massive stars.

    To learn more about this discovery and the techniques see the two papers in the journal Astronomy & Astrophysics.

    See the full article here .

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    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet


    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 4:43 pm on November 20, 2017 Permalink | Reply
    Tags: , , , , ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before, , Gemini South, ,   

    From ESO: “ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before” 

    ESO 50 Large

    European Southern Observatory

    20 November 2017
    Olivier Hainaut
    ESO
    Garching, Germany
    Tel: +49 89 3200 6752
    Email: ohainaut@eso.org

    Karen Meech
    Institute for Astronomy
    Honolulu, Hawai`i, USA
    Cell: +1-720-231-7048
    Email: meech@IfA.Hawaii.Edu

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

    1
    For the first time ever astronomers have studied an asteroid that has entered the Solar System from interstellar space. Observations from ESO’s Very Large Telescope in Chile and other observatories around the world show that this unique object was traveling through space for millions of years before its chance encounter with our star system. It appears to be a dark, reddish, highly-elongated rocky or high-metal-content object. The new results appear in the journal Nature on 20 November 2017.

    2
    This very deep combined image shows the interstellar asteroid ‘Oumuamua at the centre of the picture. It is surrounded by the trails of faint stars that are smeared as the telescopes tracked the moving asteroid. This image was created by combining multiple images from ESO’s Very Large Telescope as well as the Gemini South Telescope. The object is marked with a blue circle and appears to be a point source, with no surrounding dust. Credit: ESO/K. Meech et al.


    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    3
    This diagram shows the orbit of the interstellar asteroid ‘Oumuamua as it passes through the Solar System. Unlike all other asteroids and comets observed before, this body is not bound by gravity to the Sun. It has come from interstellar space and will return there after its brief encounter with our star system. Its hyperbolic orbit is highly inclined and it does not appear to have come close to any other Solar System body on its way in. Credit: ESO/K. Meech et al.

    4
    This plot shows how the interstellar asteroid ‘Oumuamua varied in brightness during three days in October 2017. The large range of brightness — about a factor of ten (2.5 magnitudes) — is due to the very elongated shape of this unique object, which rotates every 7.3 hours. The different coloured dots represent measurements through different filters, covering the visible and near-infrared part of the spectrum. The dotted line shows the light curve expected if ‘Oumuamua were an ellipsoid with a 1:10 aspect ratio, the deviations from this line are probably due to irregularities in the object’s shape or surface albedo. Credit: ESO/K. Meech et al.


    For the first time ever astronomers have studied an asteroid that has entered the Solar System from interstellar space. Observations from ESO’s Very Large Telescope in Chile and other observatories around the world show that this unique object was travelling through space for millions of years before its chance encounter with our star system. It appears to be a dark, reddish, highly-elongated rocky or high-metal-content object. The video is available in 4K UHD. Credit: ESO


    This animation shows the path of the interstellar asteroid 1I/2017 (‘Oumuamua) through the Solar System. Observations with ESO’s Very Large Telescope and others have shown that this unique object is dark, reddish in colour and highly elongated. Credit:ESO, M. Kornmesser, L.Calcada. Music: Azul Cobalto

    On 19 October 2017, the Pan-STARRS 1 telescope in Hawai`i picked up a faint point of light moving across the sky.

    Pann-STARS telescope, U Hawaii, Mauna Kea, Hawaii, USA, 4,207 m (13,802 ft) above sea level

    It initially looked like a typical fast-moving small asteroid, but additional observations over the next couple of days allowed its orbit to be computed fairly accurately. The orbit calculations revealed beyond any doubt that this body did not originate from inside the Solar System, like all other asteroids or comets ever observed, but instead had come from interstellar space. Although originally classified as a comet, observations from ESO and elsewhere revealed no signs of cometary activity after it passed closest to the Sun in September 2017. The object was reclassified as an interstellar asteroid and named 1I/2017 U1 (‘Oumuamua) [1].

    “We had to act quickly,” explains team member Olivier Hainaut from ESO in Garching, Germany. “’Oumuamua had already passed its closest point to the Sun and was heading back into interstellar space.”

    ESO’s Very Large Telescope was immediately called into action to measure the object’s orbit, brightness and colour more accurately than smaller telescopes could achieve. Speed was vital as ‘Oumuamua was rapidly fading as it headed away from the Sun and past the Earth’s orbit, on its way out of the Solar System. There were more surprises to come.

    Combining the images from the FORS instrument on the VLT using four different filters with those of other large telescopes, the team of astronomers led by Karen Meech (Institute for Astronomy, Hawai`i, USA) found that ‘Oumuamua varies dramatically in brightness by a factor of ten as it spins on its axis every 7.3 hours.

    ESO/FORS1

    Karen Meech explains the significance: “This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape. We also found that it has a dark red colour, similar to objects in the outer Solar System, and confirmed that it is completely inert, without the faintest hint of dust around it.”

    These properties suggest that ‘Oumuamua is dense, possibly rocky or with high metal content, lacks significant amounts of water or ice, and that its surface is now dark and reddened due to the effects of irradiation from cosmic rays over millions of years. It is estimated to be at least 400 metres long.

    Preliminary orbital calculations suggested that the object had come from the approximate direction of the bright star Vega, in the northern constellation of Lyra. However, even travelling at a breakneck speed of about 95 000 kilometres/hour, it took so long for the interstellar object to make the journey to our Solar System that Vega was not near that position when the asteroid was there about 300 000 years ago. ‘Oumuamua may well have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with the Solar System.

    Astronomers estimate that an interstellar asteroid similar to ‘Oumuamua passes through the inner Solar System about once per year, but they are faint and hard to spot so have been missed until now. It is only recently that survey telescopes, such as Pan-STARRS, are powerful enough to have a chance to discover them.

    “We are continuing to observe this unique object,” concludes Olivier Hainaut, “and we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy. And now that we have found the first interstellar rock, we are getting ready for the next ones!”

    Notes

    [1] The Pan-STARRS team’s proposal to name the interstellar objet was accepted by the International Astronomical Union, which is responsible for granting official names to bodies in the Solar System and beyond. The name is Hawaiian and more details are given here. The IAU also created a new class of objects for interstellar asteroids, with this object being the first to receive this designation. The correct forms for referring to this object are now: 1I, 1I/2017 U1, 1I/’Oumuamua and 1I/2017 U1 (‘Oumuamua). Note that the character before the O is an okina. So, the name should sound like H O u mu a mu a. Before the introduction of the new scheme, the object was referred to as A/2017 U1.

    More information

    This research was presented in a paper entitled A brief visit from a red and extremely elongated interstellar asteroid, by K. Meech et al., to appear in the journal Nature on 20 November 2017.

    The team is composed of Karen J. Meech (Institute for Astronomy, Honolulu, Hawai`i, USA [IfA]) Robert Weryk (IfA), Marco Micheli (ESA SSA-NEO Coordination Centre, Frascati, Italy; INAF–Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy), Jan T. Kleyna (IfA) Olivier Hainaut (ESO, Garching, Germany), Robert Jedicke (IfA) Richard J. Wainscoat (IfA) Kenneth C. Chambers (IfA) Jacqueline V. Keane (IfA), Andreea Petric (IfA), Larry Denneau (IfA), Eugene Magnier (IfA), Mark E. Huber (IfA), Heather Flewelling (IfA), Chris Waters (IfA), Eva Schunova-Lilly (IfA) and Serge Chastel (IfA).

    See the full article here .

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

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

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

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

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    ALMA on the Chajnantor plateau at 5,000 metres.

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    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

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    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

     
  • richardmitnick 10:09 am on September 13, 2017 Permalink | Reply
    Tags: , , , , Gemini South, Toptica Laser Successfully Installed on Gemini South Telescope   

    From Gemini: “Toptica Laser Successfully Installed on Gemini South Telescope” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    1
    On Monday, September 11 the Gemini South Operations team successfully prepped and installed the Toptica laser on the altitude platform of the telescope. In the following months, the team will test the laser interfaces and align the laser beam injector optics.

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    See the full article here .

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    Gemini/North telescope at Mauna Kea, Hawaii, USA
    Gemini/North telescope at Mauna Kea, Hawaii, USA

    Gemini South
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    AURA Icon

    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 11:20 am on February 27, 2017 Permalink | Reply
    Tags: , , , , Constraints and Conundrums, , Gemini South, GPI   

    From astrobites: “Constraints and Conundrums” 

    Astrobites bloc

    Astrobites

    Feb 27, 2017
    Mara Zimmerman

    Title: Constraints on the Architecture of the HD 95086 Planetary System with the Gemini Planet Imager
    Authors: Julien Rameau, Eric L. Nielsen, Robert J. De Rosa et al.
    Lead Author’s Insititution: Université de Montréal
    1
    Status: Accepted for publication in The Astrophysical Journal Letters open access

    HD 95086 is one of the more well studied and characterized systems; it hosts planetary, planetesimal, and dust components, which make it quite the intriguing subject to study.

    2
    An artist’s impression of a young star surrounded by debris rings and a vast dust halo. Credit: NASA/JPL-Caltech

    Its planet HD 95086 b was directly imaged by GPI in late 2013;

    GPI blocNOAO Gemini Planet Imager on Gemini South
    NOAO Gemini Planet Imager on Gemini SouthGemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile
    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

    the planet is about 4 times the mass of Jupiter and orbits its star at a distance of about 56 AU. The disk in the system is characterized by three components— a 55 K cool component, a 75 K warm component at – each of those two corresponding to a planetesimal belt– and a possible hot component at 300 K, which could suggest activity in the habitable zone of the star (Su et al. 2015). There is also quite a large gap in HD 95086’s disk, extending from about 8 to 80 AU. This system presents a perfect playground for the study of evolution and formation of unusual systems.

    3
    Figure 1: The direct images of HD 95086, taken over several epochs, are shown in this figure

    This paper focuses on constraining the orbit of HD 95086 b based on re-analyzation of old images in combination with their newer images. HD 95086 b was originally imaged in late 2013 (Galicher et al. 2014). Overall, their images spanned four epochs, from December 2013 to March 2016, and provided astromteric measurements for HD 95086 b. From these measurements, the authors found that the orbit of HD 95086 b is face-on and circular. Examples of the direct imaging on the system are shown in Figure 1.

    To constraint the orbit of HD 95086 b, the authors used Monte Carlo (MC) techniques that were more efficient than a traditional Markov Chain Monte Carlo. The technique generated parameters from a probability density function, then fit the parameters of the orbits through each epoch. The probability of the orbits generated was then evaluated by comparing the remaining epochs against a uniform random variable, and the orbits were then accepted or rejected by the program. In Figure 2, the generated orbits are shown with the data points. Using the constraints for planet b in the system, the researchers constrained the HD 95086 system as a whole.

    3
    Figure 2: The model fitting for HD 95086, overlaid with the measurements, which are color coded by date taken, is shown in this image. The gray areas indicate the approximate location of the planetesimal belts in the system.

    In an earlier publication, (Su et al. 2015), several possibilities for the system architecture were presented, and in this paper, these possibilities are explored with the new analysis of data. The authors rule out several scenarios and present the most likely scenarios from their models. The scenarios are as follows:

    Scenario A: HD 95086 b is the only planet in the system and has carved out the large gap in the disk through an eccentric orbit of about 0.7. Verdict: Ruled out with 95% confidence. Astrometric measurements from this paper do not indicate such a high eccentricity

    Scenario B: HD 95086 b has a slight eccentricity of about 0.3, and another more massive, more eccentric planet resides at 16 AU. Verdict: Neither ruled out nor confirmed. The 16 AU planet, if it were there, is undetectable by GPI, and this scenario is not constrained by the observations so a verdict for this one can’t quite be reached.

    Scenario C: Two other planets, slightly larger than HD 95086 b at about 7 Jupiter masses, orbit at 12 and 26 AU. All three planets in this scenario have low (0.3 or less) eccentricities. Verdict: Needs reconfiguration. With a low eccentricity at 26 AU, the planet would have been detected in the observations, but the inner planet at 12 AU would not have been. Its possible that the inner planet is more massive, so parts of this scenario could work with the observations. However, this scenario with two additional planets is unlikely.

    Scenario D: In addition to HD 95086, three large Jupiter-like planets, of all the same mass, orbit at 11, 19, and 34 AU, respectively. Verdict: Ruled out. The third planet, projected at 34 AU, would have been visible in observations if it were there, and this scenario would necessitate all three extra planets to account for the disk configuration.

    Certainly, these aren’t the only possibilities, but with the new analysis and data, the scenarios have been considerably confined. It is likely that HD 95086 has two massive planets that have sculpted out the gap in the disk, with one at a closer separation than is currently detectable by direct imaging. Another possibility is that three or four planets are present in the system, but their eccentricities and mass vary greatly, which could explain why they have not been detected by current observations.

    In HD 95086, planets have clearly disrupted the disk and the planetesimals, but the exact nature of this contact remains unknown, though now these researchers have found that a two-planet system of moderate eccentricity or possibly an inhomogeneous mix of three or fours planets. The interactions between the planets and the disk can reveal so much about how these systems form and evolve. There’s still some mystery left in the HD 95086 system, but the scientific sleuths of this papers have thoroughly narrowed down the possibilities.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 5:08 pm on September 15, 2016 Permalink | Reply
    Tags: , , Gemini South, Nearby Exo-Earth Family Withstands Extreme Scrutiny, TRAPPIST-1 M-type star   

    From Gemini: “Nearby Exo-Earth Family Withstands Extreme Scrutiny” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    September 9, 2016
    Science Contacts:
    Dr. Steve B. Howell
    Project Scientist, NASA K2 Mission
    NASA Ames Research Center
    steve.b.howell@nasa.gov
    Desk: 650.604.4238
    Cel: 520.461.6925

    Dr. Elliott P. Horch
    Professor of Physics, Southern Connecticut State University
    horche2@southernct.edu
    Desk: 203-392-6393
    Cell: 203-214-4310

    Media Contacts:

    Peter Michaud
    Gemini Observatory
    Hilo, Hawai‘i
    pmichaud@gemini.edu
    Desk: (56) 51-2205-628
    Available (in Chile) until 9/12/16

    Manuel Paredes
    Gemini Observatory
    Gemini South Base Facility, La Serena, Chile
    mparedes@gemini.edu
    Cell: (56) 51-2205-671

    1
    Artist’s concept of what the view might be like from inside the TRAPPIST-1 exoplanetary system showing three Earth-sized planets in orbit around the low-mass star. This alien planetary system is located only 40 light years away. Gemini South telescope imaging, the highest resolution images ever taken of the star, revealed no additional stellar companions providing strong evidence that three small, probably rocky planets orbit this star. Credit: Robert Hurt/JPL/Caltech.

    Astronomers combined the power of the 8-meter Gemini South telescope in Chile with an extremely high-resolution camera to scrutinize the star TRAPPIST-1. Previous observations of the star, which is only about 8% the mass of our Sun, revealed dips in the star’s light output that would be expected if several Earth-sized planets orbited the star. However, the situation would be greatly complicated if, upon closer examination, the star was found to have a yet-unseen stellar companion.

    No such companion was found with Gemini, which essentially seals the case for multiple Earth-sized planets orbiting TRAPPIST-1.

    Steve Howell of NASA’s Ames Research Center led the extremely high-resolution observations using the Differential Speckle Survey Instrument (DSSI), an instrument he has used before at both Gemini telescopes to probe other exoplanetary systems. The new observations reinforced the hypothesis that several Earth-sized planets are responsible for the fluctuations in the star’s brightness. “By finding no additional stellar companions in the star’s vicinity we confirm that a family of smallish planets orbit this star,” says Howell. “Using Gemini we can see closer to this star than the orbit of Mercury to our Sun. Gemini with DSSI is unique in being able to do this, bar none.”

    The research, led by Howell, is published in the September 13th issue of The Astrophysical Journal Letters.

    TRAPPIST-1 is what astronomers call a late M-type star; stars which are small, ultra-cool (compared to most stars), and faint. Late M stars are so faint that the only specimens we can observe are relatively close-by in space and, as the Gemini observations demonstrate, allow astronomers to probe very close to these stars in the search for companions.

    “While no current telescope can actually image an Earth-size planet around another star, even if orbiting a nearby star such as TRAPPIST-1, our instrument on Gemini allows us to detect close companion stars and even brown dwarfs.” says Elliott Horch, [Southern Connecticut State University] co-author of the paper. “Such observations validate not only the existence of exoplanets, but their small size as well.”

    M stars are of great interest to astronomers today as their diminutive size allows easier detection of small, Earth-size planets. The intrinsic faintness of M stars means that potentially habitable planets will have short orbital periods, on the order of weeks. Such planets will be the targets of detailed study by both ground- and space-based telescopes, studies that will attempt to measure the composition of their atmospheres and see if they are indeed Earth-like beyond just their size.

    The discovery of TRAPPIST-1’s likely exoplanet pedigree began late in 2015 with data from the TRAPPIST (the TRansiting Planets and PlanetesImals Small Telescope) project.

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

    This work, published in the 12 May 2016 issue of the journal Nature, and led by Michael Gillon, observed TRAPPIST-1 over 62 nights. During that period, the star was found to fluctuate in a manner that is consistent with at least three Earth-sized planets orbiting and periodically eclipsing and blocking part of the star’s light from our view on the Earth. While work is still ongoing to refine the total number of planets, two of them appear to orbit in 1.5 and 2.4 days and are so close that they receive four and two times the radiation that our Earth receives from the Sun, respectively. The third planet is more difficult to characterize, having possible orbital periods between 4 to 73 days. However, this third planet’s most likely period, 18 days, would place this world well within the system’s habitable-zone where liquid water could exist on its surface.

    The Gemini observations, made with the DSSI instrument, were made during a temporary visit of the instrument at the Gemini South telescope in Chile. “Gemini’s flourishing Visitor Instrument program is producing superb results in all areas of astronomy,” said Chris Davis, a program director at the U.S. National Science Foundation, one of the agencies that funds the International Gemini Observatory and which also provided initial funding for DSSI. “The DSSI observations of the TRAPPIST-1 system of exoplanets is just one example. The instrument team and their collaborators deserve credit for building such a versatile and productive instrument and also for making it available to all of Gemini’s users.”

    The DSSI instrument on Gemini provides a unique capability to characterize the environment around exoplanetary systems. The instrument provides extreme-resolution images by taking multiple extremely short (60 millisecond) exposures of a star to capture fine detail and “freeze” the turbulence caused by the Earth’s atmosphere. By combining the images and removing the momentary distortions caused by the Earth’s atmosphere, the final images yield a resolution equal to what the telescope would produce if it was in space. With this technique, called speckle interferometry, astronomers can see details at, or very near, the theoretical limit of the 8-meter Gemini mirror yielding the highest-resolution single telescope images available to astronomers. The available resolution is like being able to separate an automobile’s two headlights at a distance of about 2000 miles.

    See the full article here .

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    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
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    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
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