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  • richardmitnick 4:12 pm on November 19, 2014 Permalink | Reply
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    From ALMA: “Chilean astronomers using ALMA discover new clues about massive star formation” 

    ESO ALMA Array
    ALMA

    Wednesday, 19 November 2014
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

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

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    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

    Astronomers using the ALMA radio telescope detected that the supersonic jet and the accretion disk survives the ultraviolet radiation generated by the birth of a massive star. This discovery refutes existing theories, indicating that ultraviolet radiation from the star would destroy molecular gas and dust, and bringing the first direct detection of ionized gas wind along with a supersonic jet and an accretion disk. The research results were published in The Astrophysical Journal.

    Massive stars emit a large amount of ultraviolet radiation that destroys the molecules and dust surrounding the star and creates ionized gas, which in turn impedes the star’s growth process. This is why previous theories have suggested that the model of a small star forming from a protoplanetary gas and dust disk isn’t applicable to high mass stars. According to the study published today, dust and molecular gas can survive the destructive effects of ultraviolet radiation that accompanies the birth of a massive star.

    1
    Fig. 1: Spectrum showing the line of hydrogen recombination observed with ALMA looking toward the massive protostar G345.4938+01.4677. The shape of the spectral line in the area indicated by the rectangles is consistent with the theory of broadening in the presence of electric fields known as the Stark effect, detected for the first time so clearly in this observation. The blue dotted line shows the theoretical prediction of the Stark effect.

    The young star that was studied, G345.4938+01.4677, is located in the Scorpius constellation and has a mass 15 times greater than the Sun. This is where scientists made at least three important discoveries. “The first thing we detected is a supersonic stream emerging from the star forming inside the ionized gas region. This suggests that the accretion disk and gas stream are strong enough to survive despite the damage caused by ultraviolet light,” explained Andrés Guzmán, the study’s principal researcher and a postdoctoral fellow at the University of Chile.

    ALMA’s cutting-edge technology enable astronomers to get, for the first time, evidence of the effect of electric fields on the emission of lines of hydrogen. “The detection of this so called Stark effect was possible due to the high density of gas around this star and ALMA’s extraordinary sensitivity,” said Guido Garay, Director of the Astronomy Department at the University of Chile and a co-author of the study.

    “Thanks to the sensitivity and high angular resolution of ALMA we could for the first time detect a rotating disk around a massive star and effects of electric fields on the hydrogen line emission from a jet from the same star”, added Lars Nyman, Head of Science Operations at the JAO ALMA Observatory and co-author of the study.

    2
    Fig. 2: Image in the infrared spectrum near G345.4938+01.4677 obtained by the VVV project using the VISTA telescope at Cerro Paranal Observatory. In the lower left corner is a close-up of the central area, showing the cavity created by the jet stream. In the center of the image the young high mass star appears as a small and weak red spot.

    ESO Vista Telescope
    ESO/VISTA

    ESO Cerro Paranal
    ESO/ Cerro Paranal Observatory

    The third major milestone is the discovery of molecular gas and dust rotating around the massive star. This discovery extends the observation of protoplanetary disks to the high mass regime, where the dynamic is dominated by the mass of the disk rather than the mass of the central star. Even though it was estimated that there are 56 solar masses in the disk, compared to 15 solar masses in the central star, the disk’s rotation is perfectly aligned with the stream of ionized gas, suggesting that the supersonic gas stream is being accelerated and aligned from an accretion disk.

    In the near future, “we expect to find and study more streams associated with these kinds of hyper-compact ionized regions. Without ALMA it would have been impossible to better characterize the accretion in this massive star and determine whether it is part of a binary system,” Guzmán concluded.

    3
    Fig. 3: The coloured area is where ALMA detected emission of sulfur dioxide molecules toward G345.4938+01.4677. The colours indicate the velocity of the gas: blue shows it coming closer, while red shows it moving away. The colour distribution observed is characteristic of material rotating in protoplanetary disks around the protostar. The curved arrow shows the direction of the rotation, indicating that the stream material is ejected through the poles of the disk. | Download

    More Information

    Twenty-five ALMA antennas were used to make this discovery in 2013.

    The scientists who conducted the study include University of Chile astronomers Andrés Guzmán (principal researcher), Guido Garay (Astronomy Department Director), Leonardo Bronfman, and Diego Mardones, as well as Luis Rodríguez (UNAM Center for Radio Astronomy and Astrophysics), James M. Moran (Harvard-Smithsonian Center for Astrophysics), Kate Brooks (Center for Astronomy and Space Science, CSIRO-Australia) and Lars-Ake Nyman (Joint ALMA Observatory).

    Link to article in The Astrophysical Journal.

    See the full article here.

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    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.

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  • richardmitnick 1:25 pm on November 11, 2014 Permalink | Reply
    Tags: ALMA, , , , ,   

    From ALMA: “ALMA Finds Best Evidence Yet for Galactic Merger in Distant Protocluster “ 

    ESO ALMA Array
    ALMA

    Tuesday, 11 November 2014
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    Email: cblue@nrao.edu

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

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Nestled among a triplet of young galaxies more than 12.5 billion light-years away is a cosmic powerhouse: a galaxy that is producing stars nearly 1,000 times faster than our own Milky Way. This energetic starburst galaxy, known as AzTEC-3, together with its gang of calmer galaxies may represent the best evidence yet that large galaxies grow from the merger of smaller ones in the early Universe, a process known as hierarchical merging.

    conc
    Artist’s impression of the protocluster observed by ALMA. It shows the central starburst galaxy AzTEC-3 along with its labeled cohorts of smaller, less active galaxies. New ALMA observations suggest that AzTEC-3 recently merged with another young galaxy and that the whole system represents the first steps toward forming a galaxy cluster. | Credit: B. Saxton (NRAO/AUI/NSF)

    An international team of astronomers observed these remarkable objects with the Atacama Large Millimeter/submillimeter Array (ALMA).

    “The ALMA data reveal that AzTEC-3 is a very compact, highly disturbed galaxy that is bursting with new stars at close to its theoretically predicted maximum limit and is surrounded by a population of more normal, but also actively star-forming galaxies,” said Dominik Riechers, an astronomer and assistant professor at Cornell University in Ithaca, New York, and lead author on a paper published today (Nov. 11) in the Astrophysical Journal. “This particular grouping of galaxies represents an important milestone in the evolution of our Universe: the formation of a galaxy cluster and the early assemblage of large, mature galaxies.”

    In the early Universe, starburst galaxies like AzTEC-3 were forming new stars at a monstrous pace fueled by the enormous quantities of star-forming material they devoured and by merging with other adolescent galaxies. Over billions of years, these mergers continued, eventually producing the large galaxies and clusters of galaxies we see in the Universe today.

    Evidence for this hierarchical model of galaxy evolution has been mounting, but these latest ALMA data show a strikingly clear picture of the all-important first steps along this process when the Universe was only 8 percent of its current age.

    “One of the primary science goals of ALMA is the detection and detailed study of galaxies throughout cosmic time,” said Chris Carilli, an astronomer with the National Radio Astronomy Observatory in Socorro, New Mexico. “These new observations help us put the pieces together by showing the first steps of a galaxy merger in the early Universe.”

    AzTEC-3, which is located in the direction of the constellation Sextans, is what astronomers refer to as a submillimeter galaxy, since it shines brightly in that portion of the spectrum, but is remarkably dim at optical and infrared wavelengths. This is due to light from its stars being absorbed by dust in the star-forming environments of the galaxy and then reemitted by the dust at far-infrared wavelengths. As this light travels across the cosmos, it becomes stretched due to the expansion of the Universe, so by the time it arrives at Earth, the far-infrared light has shifted to the submillimeter/millimeter portion of the spectrum.

    sf
    Image of the star-forming gas in AzTEC-3 (upper right) and its neighbor LBG-1 (lower left) observed by ALMA. This portion of the ALMA data only identifies galaxies at the distance of AzTEC-3. | Credit: ALMA (NRAO/NAOJ/ESO); B. Saxton (NRAO/AUI/NSF)

    ALMA, with its remarkable sensitivity and high resolving power, was able to observe this system at these wavelengths in unprecedented detail. It also was able to study, for the first time, the star-forming gas in three additional, extremely distant members of an emerging galactic protocluster.

    The ALMA data revealed that the three smaller, more normal galaxies are indeed producing stars from their gas at a relatively calm and steady pace. Unlike its neighbors, however, AzTEC-3 is burning through star-forming fuel at breakneck speed. Indeed, AzTEC-3 appears to form more new stars each day than our Milky Way galaxy forms in an entire year — outpacing the normal galaxies in its proximity by about a factor of 100.

    The researchers also observed very little rotation in AzTEC-3′s dust and gas — suggesting that something had disrupted its motion. Taken together, these two characteristics are strong indications that AzTEC-3 recently merged with another galaxy.

    three
    Combined data from Japan’s Subaru telescope and ALMA of the AzTEC-3 region; the circled regions are members of this protocluster, which were previously highlighted by Subaru. The ALMA data are highlighted with arrows. | Credit: Subaru/NASA/JPL, P. Capak (SSC/Caltech); B. Saxton (NRAO/AUI/NSF)

    NAOJ Subaru TelescopeNAOJ Subaru Telescope interior
    NAOJ/Subaru

    “AzTEC-3 is currently undergoing an extreme, but short-lived event,” said Riechers. “This is perhaps the most violent phase in its evolution, leading to a star formation activity level that is very rare at its cosmic epoch.”

    The astronomers believe that AzTEC-3 and the other nearby galaxies appear to be part of the same system, but are not yet gravitationally bound into a clearly defined cluster. This is why the astronomers refer to them collectively as a protocluster.

    The starburst galaxy was originally observed with and named after the AzTEC millimeter-wavelength camera, which was installed at the time on the James Clerk Maxwell Telescope, a single-dish radio telescope located on Mauna Kea, Hawaii. Only with ALMA has it become possible to understand the nature of this exceptional galaxy and those in its immediate environment.

    James Clerk Maxwell Telescope
    James Clerk Maxwell Telescope interior
    James Clerk Maxwell Telescope

    See the full article here.

    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.

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  • richardmitnick 3:48 pm on November 6, 2014 Permalink | Reply
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    From ALMA: “Revolutionary ALMA Image Reveals Planetary Genesis” 

    ESO ALMA Array
    ALMA

    Wednesday, 05 November 2014

    Catherine Vlahakis
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 9 75515736
    Email: cvlahaki@alma.cl

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

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

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    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

    A new image from ALMA, the Atacama Large Millimeter/submillimeter Array, reveals extraordinarily fine detail that has never been seen before in the planet-forming disc around a young star. ALMA’s new high-resolution capabilities were achieved by spacing the antennas up to 15 kilometers apart [1]. This new result represents an enormous step forward in the understanding of how protoplanetary discs develop and how planets form.

    ALMA has obtained its most detailed image yet showing the structure of the disc around HL Tau [2], a million-year-old Sun-like star located approximately 450 light-years from Earth in the constellation of Taurus. The image exceeds all expectations and reveals a series of concentric and bright rings, separated by gaps.

    f1
    Fig. 1 (top): This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. These new ALMA observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system. Credit: ALMA (ESO/NAOJ/NRAO).

    f2
    Fig. 2 (left): This is a composite image of the young star HL Tauri and its surroundings using data from ALMA (enlarged in box at upper right) and the NASA/ESA Hubble Space Telescope (rest of the picture). This is the first ALMA image where the image sharpness exceeds that normally attained with Hubble. Credit: ALMA (ESO/NAOJ/NRAO)/NASA/ESA

    f3
    Fig. 3 (right): This image compares the size of the Solar System with HL Tauri and its surrounding protoplanetary disc. Although the star is much smaller than the Sun, the disc around HL Tauri stretches out to almost three times as far from the star as Neptune is from the Sun. Credit: ALMA (ESO/NAOJ/NRAO)

    “These features are almost certainly the result of young planet-like bodies that are being formed in the disc. This is surprising since such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image,” said Stuartt Corder, ALMA Deputy Director.

    “When we first saw this image we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disc appears to be full of forming planets. This one image alone will revolutionize theories of planet formation,” explained Catherine Vlahakis, ALMA Deputy Program Scientist and Lead Program Scientist for the ALMA Long Baseline Campaign.

    Such a resolution can only be achieved with the long baseline capabilities of ALMA and provides astronomers with new information that is impossible to collect with any other facility, even the Hubble Space Telescope. “The logistics and infrastructure required to place antennas at such distant locations required an unprecedented coordinated effort for the international expert team of engineers and scientists” said ALMA Director, Pierre Cox. “These long baselines fulfill one of ALMA’s major objectives and mark an impressive technological, scientific and engineering milestone”, celebrated Cox.

    Stars like HL Tau and our own Sun form within clouds of gas and dust that collapse under gravity. Over time, the surrounding dust particles stick together, growing into sand, pebbles, and larger-size rocks, which eventually settle into a thin disc where asteroids, comets, and planets form. Once these planetary bodies acquire enough mass, they dramatically reshape the structure of the disc, fashioning rings and gaps as the planets sweep their orbits clear of debris and shepherd dust and gas into tighter and more confined zones.

    f4
    Fig. 4: This is an artist’s impression of a young star surrounded by a protoplanetary disc in which planets are forming. Using ALMA’s 15-kilometre baseline astronomers were able to make the first detailed image of a protoplanetary disc, which revealed the complex structure of the disc. Concentric rings of gas, with gaps indicating planet formation, are visible in this artist’s impression and were predicted by computer simulations. Now these structures have been observed by ALMA for the first time. Credit: ESO/L. Calçada

    In the visible, HL Tau is partly obscured by the massive cloud of dust and gas that surrounds it. ALMA operates in such a way that it can see through the cloud and study the processes right at the center. This new ALMA image provides the clearest evidence to date that not only does this process occur, but also that it is faster than previously thought.

    The investigation of these protoplanetary discs is essential to our understanding of how Earth formed in the Solar System. Observing the first stages of planet formation around HL Tauri may show us how our own planetary system may have looked more than four billion years ago, when it formed.

    Notes

    [1] Since September 2014 ALMA has been observing the Universe using its longest ever baselines, with antennas separated by up to 15 kilometers. This Long Baseline Campaign will continue until 1 December 2014. The baseline is the distance between two of the antennas in the array. As a comparison, other facilities operating at millimeter wavelengths provide antennas separated by no more than two kilometers. The maximum possible ALMA baseline is 16 kilometers. Future observations at shorter wavelengths will achieve even higher image sharpness.

    [2] The structures are seen with a resolution of just five times the distance from the Sun to the Earth. This corresponds to an angular resolution of about 35 milliarcseconds — better than what is routinely achieved with the NASA/ESA Hubble Space Telescope.

    See the full article, with videos, here.

    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.

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  • richardmitnick 3:45 pm on October 29, 2014 Permalink | Reply
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    From ALMA: “Planet-forming Lifeline Discovered in a Binary Star System” 

    ESO ALMA Array
    ALMA

    Wednesday, 29 October 2014

    Anne Dutrey
    Laboratoire d’Astrophysique de Bordeaux
    University Bordeaux/CNRS – France
    Tel: +33 5 57 776140
    Email: Anne.Dutrey@obs.u-bordeaux1.fr

    Emmanuel DiFolco
    Laboratoire d’Astrophysique de Bordeaux
    University Bordeaux/CNRS France
    Tel: +33 5 57 776136
    Email: Emmanuel.Difolco@obs.u-bordeaux1.fr

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

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

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    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

    For the first time, researchers using ALMA have detected a streamer of gas flowing from a massive outer disc toward the inner reaches of a binary star system. This never-before-seen feature may be responsible for sustaining a second, smaller disc of planet-forming material that otherwise would have disappeared long ago. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets. The results are published in the journal Nature on October 30, 2014.

    A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France and CNRS used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the distribution of dust and gas in a multiple-star system called GG Tau-A [1]. This object is only a few million years old and lies about 450 light-years from Earth in the constellation of Taurus (The Bull).

    Like a wheel in a wheel, GG Tau-A contains a large, outer disc encircling the entire system as well as an inner disc around the main central star. This second inner disc has a mass roughly equivalent to that of Jupiter. Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.

    sytar
    Fig. 1: This artist’s impression shows the dust and gas around the double star system GG Tauri-A. Researchers using ALMA have detected gas in the region between two discs in this binary system. This may allow planets to form in the gravitationally perturbed environment of the binary. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets. Credit: ESO/L. Calçada

    While observing these structures with ALMA, the team made the exciting discovery of gas clumps in the region between the two discs. The new observations suggest that material is being transferred from the outer to the inner disc, creating a sustaining lifeline between the two [2].

    “Material flowing through the cavity was predicted by computer simulations but has not been imaged before. Detecting these clumps indicates that material is moving between the discs, allowing one to feed off the other,” explains Dutrey. “These observations demonstrate that material from the outer disc can sustain the inner disc for a long time. This has major consequences for potential planet formation.”

    Planets are born from the material left over from star birth. This is a slow process, meaning that an enduring disc is a prerequisite for planet formation. If the feeding process into the inner disc now seen with ALMA occurs in other multiple-star systems the findings introduce a vast number of new potential locations to find exoplanets in the future.

    The first phase of exoplanet searches was directed at single-host stars like the Sun [3]. More recently it has been shown that a large fraction of giant planets orbit binary-star systems. Now, researchers have begun to take an even closer look and investigate the possibility of planets orbiting the individual stars of multiple-star systems. The new discovery supports the possible existence of such planets, giving exoplanet discoverers new happy hunting grounds.

    Emmanuel Di Folco, co-author of the paper, concludes: “Almost half the Sun-like stars were born in binary systems. This means that we have found a mechanism to sustain planet formation that applies to a significant number of stars in the Milky Way. Our observations are a big step forward in truly understanding planet formation.”

    Notes

    [1] GG Tau-A is part of a more complex multiple-star system called GG Tauri. Recent observations of GG Tau-A using the VLTI have revealed that one of the stars — GG Tau Ab, the one not surrounded by a disc — is itself a close binary, consisting of GG Tau-Ab1 and GG Tau-Ab2. This introduced a fifth component to the GG Tau system.

    ESO VLT Interferometer
    ESO VLTI

    [2] An earlier result with ALMA showed an example of a single star with material flowing inwards from the outer part of its disc.

    [3] Because orbits in binary stars are more complex and less stable, it was believed that forming planets in these systems would be more challenging than around single stars.

    More Information

    This research was presented in a paper entitled Planet formation in the young, low-mass multiple stellar system GG Tau-A” by A. Dutrey et al., to appear in the journal Nature.

    The team is composed of Anne Dutrey (University Bordeaux/CNRS, France), Emmanuel Di Folco (University Bordeaux/CNRS), Stephane Guilloteau (University Bordeaux/CNRS), Yann Boehler (University of Mexico, Michoacan, Mexico), Jeff Bary (Colgate University, Hamilton, USA), Tracy Beck (Space Telescope Science Institute, Baltimore, USA), Hervé Beust (IPAG, Grenoble, France), Edwige Chapillon (University Bordeaux/IRAM, France), Fredéric Gueth (IRAM, Saint Martin d’Hères, France), Jean-Marc Huré (University Bordeaux/CNRS), Arnaud Pierens (University Bordeaux/CNRS), Vincent Piétu (IRAM), Michal Simon (Stony Brook University, USA) and Ya-Wen Tang (Academia Sinica Institute of Astronomy and Astrophysics, Taipei, Taiwan).

    See the full article here.

    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

    ScienceSprings relies on technology from

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    Lenovo
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  • richardmitnick 1:26 pm on October 22, 2014 Permalink | Reply
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    From NASA Goddard: “NASA-led Study Sees Titan Glowing at Dusk and Dawn” 

    NASA Goddard Banner

    October 22, 2014
    Nancy Neal-Jones 301-286-0039
    nancy.n.jones@nasa.gov
    Elizabeth Zubritsky 301-614-5438
    Goddard Space Flight Center, Greenbelt, Md.
    elizabeth.a.zubritsky@nasa.gov

    New maps of Saturn’s moon Titan reveal large patches of trace gases shining brightly near the north and south poles. These regions are curiously shifted off the poles, to the east or west, so that dawn is breaking over the southern region while dusk is falling over the northern one.

    two
    High in the atmosphere of Titan, large patches of two trace gases glow near the north pole, on the dusk side of the moon, and near the south pole, on the dawn side. Brighter colors indicate stronger signals from the two gases, HNC (left) and HC3N (right); red hues indicate less pronounced signals.
    Image Credit: NRAO/AUI/NSF

    The pair of patches was spotted by a NASA-led international team of researchers investigating the chemical make-up of Titan’s atmosphere.

    “This is an unexpected and potentially groundbreaking discovery,” said Martin Cordiner, an astrochemist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of the study. “These kinds of east-to-west variations have never been seen before in Titan’s atmospheric gases. Explaining their origin presents us with a fascinating new problem.”

    The mapping comes from observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), a network of high-precision antennas in Chile. At the wavelengths used by these antennas, the gas-rich areas in Titan’s atmosphere glowed brightly. And because of ALMA’s sensitivity, the researchers were able to obtain spatial maps of chemicals in Titan’s atmosphere from a “snapshot” observation that lasted less than three minutes.

    ALMA Array
    ALMA Array

    Titan’s atmosphere has long been of interest because it acts as a chemical factory, using energy from the sun and Saturn’s magnetic field to produce a wide range of organic, or carbon-based, molecules. Studying this complex chemistry may provide insights into the properties of Earth’s very early atmosphere, which may have shared many chemical characteristics with present-day Titan.

    In this study, the researchers focused on two organic molecules, hydrogen isocyanide (HNC) and cyanoacetylene (HC3N), that are formed in Titan’s atmosphere. At lower altitudes, the two molecules appear concentrated above Titan’s north and south poles. These findings are consistent with observations made by NASA’s Cassini spacecraft, which has found a cloud cap and high concentrations of some gases over whichever pole is experiencing winter on Titan.

    NASA Cassini Spacecraft
    NASA/Cassini

    The surprise came when the researchers compared the gas concentrations at different levels in the atmosphere. At the highest altitudes, the gas pockets appeared to be shifted away from the poles. These off-pole locations are unexpected because the fast-moving winds in Titan’s middle atmosphere move in an east–west direction, forming zones similar to Jupiter’s bands, though much less pronounced. Within each zone, the atmospheric gases should, for the most part, be thoroughly mixed.

    The researchers do not have an obvious explanation for these findings yet.

    “It seems incredible that chemical mechanisms could be operating on rapid enough timescales to cause enhanced ‘pocket’’ in the observed molecules,” said Conor Nixon, a planetary scientist at Goddard and a coauthor of the paper, published online today in the Astrophysical Journal Letters. “We would expect the molecules to be quickly mixed around the globe by Titan’s winds.”

    At the moment, the scientists are considering a number of potential explanations, including thermal effects, previously unknown patterns of atmospheric circulation, or the influence of Saturn’s powerful magnetic field, which extends far enough to engulf Titan.

    Further observations are expected to improve the understanding of the atmosphere and ongoing processes on Titan and other objects throughout the solar system.

    NASA’s Astrobiology Program supported this work through a grant to the Goddard Center for Astrobiology, a part of the NASA Astrobiology Institute. Additional funding came from NASA’s Planetary Atmospheres and Planetary Astronomy programs. ALMA, an international astronomy facility, is funded in Europe by the European Southern Observatory, in North America by the U.S. National Science Foundation in cooperation with the National Research Council of Canada and the National Science Council of Taiwan, and in East Asia by the National Institutes of Natural Sciences of Japan in cooperation with the Academia Sinica in Taiwan.

    See the full article here.

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

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

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  • richardmitnick 3:41 pm on October 8, 2014 Permalink | Reply
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    From ALMA: “ALMA, a natural laboratory for high-altitude medicine” 

    ESO ALMA Array
    ALMA

    Wednesday, 01 October 2014
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Health experts took part in an important multidisciplinary meeting at the ALMA Observatory facilities, where they shared experiences and research on medicine at high geographic altitude, with a particular focus on a condition known as intermittent hypoxia –lack of oxygen– which has only been studied among mountain climbers.

    About 50 people participated in the seminar, which was held on September 23-25 at the Operation Support Facility (OSF, at 2,900 meters altitude). Those attending included the Latin America Health Manager for Barrick Gold Corporation; the Health Superintendent at Toromocho mine in Peru; representatives of Carabineros de Chile (the uniformed police); the Chilean Safety Association; the APEX Observatory; executives from Indura, Correa Ingeniería, ESACHS and Medicina de Altura; and medical specialists from the University of Calgary in Canada, Universidad Católica del Norte, Universidad de Chile and Tocopilla Hospital.

    team
    Fig. 1: Medical team observing eye fundus and monitoring heart with a telemedicine machine that can be controlled from all over the world through an internet connection. Credit: ALMA(ESO/NAOJ/NRAO), Carlos Padilla

    “ALMA offers a unique opportunity to study physiological adaptation and human action at high geographic altitude,” said Marc Poulin, a doctor from the University of Calgary. “In addition to its location at high altitude, people from all over the world work at ALMA. Therefore, it’s an interdisciplinary and multicultural environment where specialists like us hope to advance the knowledge frontier in terms of what the human body can do.”

    Members of communities that have historically lived at high geographic altitude have succeeded in adapting to lower oxygen levels by changing habits such as diet in order to enjoy a better quality of life. This acclimation, however, is not so easy for those who work in shifts at high altitudes –such as at astronomical observatories or mines–but who live closer to sea level.

    “The Chilean model is different from the rest of the world because the ocean and the mountains are so close together,” said Daniel Jiménez, a doctor who led a legal reform effort that has placed Chile at the forefront of this area. “The result is that thousands of people travel from the coast to high altitudes, especially due to mining work scheduled in weekly shifts.” Jiménez explained that this special phenomenon has been of interest for diverse areas of medicine, with the study of the resulting disorders.

    two
    Fig. 2: ALMA staff drawing the Complex Rey-Osterrieth Figure at 5.000 meters above sea level in a pressurized room. Credit: ALMA(ESO/NAOJ/NRAO), Carlos Padilla |

    ALMA is unique because its employees work at an altitude of 2,900 meters–where its offices, laboratories and camp are located–but they sometimes also work at 5,000 meters, where its antennas are located. Rapid, intermittent exposure to low oxygen levels –known as chronic intermittent hypobaric hypoxia– can cause various illnesses that must be prevented, such as acute mountain sickness (known in Chile as puna), polyglobulia (excess production of red blood cells), brain swelling, acute pulmonary edema and sleep disorders.

    “Sleep disorders are defined as sleeping less than 6 hours per day due to sleep fragmentation and insomnia, which produces sleepiness the following day and also fatigue that has impacts on work. This is especially dangerous for drivers. The new Chilean law is aimed at preventing these illnesses,” said Dr. Jiménez.

    To empirically experience variation in oxygen levels, the conference members participated in an exercise at the Array Operations Site (AOS), more than 5.000 meters above sea level, that consisted of memorizing an image and then drawing it twice. The first drawing was done with an oxygen supplement and then, 15 minutes later, without extra oxygen. The results were conclusive (see drawings below).

    dwg
    Fig. 3: Rey-Osterrieth Complex Figure

    To reduce the risk associated with hypoxia, the specialists recommended changing habits, mainly through a diet that is lower in calories and contains more liquids, and ensuring good sleep habits, such as going to bed early. In a joint project with Chilean universities, ALMA is also studying the effects of working at high altitude on target groups such as smokers.

    See the full article here.

    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.

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  • richardmitnick 7:50 pm on September 30, 2014 Permalink | Reply
    Tags: ALMA, , , , , ,   

    From Astronomy: “New molecule found in space connotes life origins” 

    Astronomy magazine

    Astronomy Magazine

    September 29, 2014
    No Writer Credit
    Cornell University, Ithaca, New York

    Like finding a molecular needle in a cosmic haystack, astronomers have detected radio waves emitted by isopropyl cyanide.

    Hunting from a distance of 27,000 light-years, astronomers have discovered an unusual carbon-based molecule — one with a branched structure — contained within a giant gas cloud in interstellar space. Like finding a molecular needle in a cosmic haystack, astronomers have detected radio waves emitted by isopropyl cyanide. The discovery suggests that the complex molecules needed for life may have their origins in interstellar space.

    cyan
    Dust and molecules in the central region of our galaxy: The background image shows the dust emission in a combination of data obtained with the APEX telescope and the Planck space observatory at a wavelength around 860 micrometers. The organic molecule iso-propyl cyanide with a branched carbon backbone (i-C3H7CN, left) as well as its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right) were both detected with the Atacama Large Millimeter/submillimeter Array in the star-forming region Sgr B2, about 300 light years away from the galactic center Sgr A*.
    MPIfR/A. Weiß (background image); University of Cologne/M. Koerber (molecular models); MPIfR/A. Belloche (montage)

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), researchers studied the gaseous star-forming region Sagittarius B2.

    ALMA Array
    ALMA

    Organic molecules usually found in these star-forming regions consist of a single “backbone” of carbon atoms arranged in a straight chain. But the carbon structure of isopropyl cyanide branches off, making it the first interstellar detection of such a molecule, said Rob Garrod from Cornell University in Ithaca, New York.

    This detection opens a new frontier in the complexity of molecules that can be formed in interstellar space and that might ultimately find their way to the surfaces of planets, said Garrod. The branched carbon structure of isopropyl cyanide is a common feature in molecules that are needed for life — such as amino acids, which are the building blocks of proteins. This new discovery lends weight to the idea that biologically crucial molecules, like amino acids that are commonly found in meteorites, are produced early in the process of star formation — even before planets such as Earth are formed.

    Garrod, along with Arnaud Belloche and Karl Menten, both of the Max Planck Institute for Radio Astronomy, and Holger Müller of the University of Cologne, sought to examine the chemical makeup of Sagittarius B2, a region close to the Milky Way’s galactic center and an area rich in complex interstellar organic molecules.

    With ALMA, the group conducted a full spectral survey looking for fingerprints of new interstellar molecules — with sensitivity and resolution 10 times greater than previous surveys.

    The purpose of the ALMA Observatory is to search for cosmic origins through an array of 66 sensitive radio antennas from the high elevation and dry air of northern Chile’s Atacama Desert. The array of radio telescopes works together to form a gigantic “eye” peering into the cosmos.

    “Understanding the production of organic material at the early stages of star formation is critical to piecing together the gradual progression from simple molecules to potentially life-bearing chemistry,” said Belloche.

    About 50 individual features for isopropyl cyanide and 120 for normal-propyl cyanide — its straight-chain sister molecule — were identified in the ALMA spectrum of the Sagittarius B2 region. The two molecules — isopropyl cyanide and normal-propyl cyanide — are also the largest molecules yet detected in any star-forming region.

    See the full article here..

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  • richardmitnick 4:24 pm on September 25, 2014 Permalink | Reply
    Tags: ALMA, , , , , ,   

    From SPACE.com: “Newfound Molecule in Space Dust Offers Clues to Life’s Origins” 

    space-dot-com logo

    SPACE.com

    September 25, 2014
    Megan Gannon

    The discovery of a strangely branched organic molecule in the depths of interstellar space has capped a decades-long search for the carbon-bearing stuff.

    life
    The organic molecule iso-propyl cyanide has a branched carbon backbone (i-C3H7CN, left), unlike its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right). Both molecules were detected with ALMA in Sagittarius B2. Credit: MPIfR/A. Weiss, University of Cologne/M. Koerber, MPIfR/A. Belloche

    The molecule in question — iso-propyl cyanide (i-C3H7CN) — was spotted in Sagittarius B2, a huge star-making cloud of gas and dust near the center of the Milky Way, about 27,000 light-years from the sun. The discovery suggests that some of the key ingredients for life on Earth could have originated in interstellar space.

    A specific molecule emits light at a particular wavelength and in a telltale pattern, or spectrum, which scientists can detect using radio telescopes. For this study, astronomers used the enormous Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the Chilean desert, which went online last year and combines the power of 66 radio antennas.

    ALMA Array
    ALMA Array

    Iso-propyl cyanide joins a long list of molecules detected in interstellar space. But what makes this discovery significant is the structure of iso-propyl cyanide. All other organic molecules that have been detected in space so far (including normal-propyl cyanide, the sister of i-C3H7CN) are made of a straight chain with a carbon backbone. Iso-propyl cyanide, however, has a “branched” structure. This same type of branched structure is a key characteristic of amino acids.

    “Amino acids are the building blocks of proteins, which are important ingredients of life on Earth,” the study’s lead author, Arnaud Belloche, of the Max Planck Institute for Radio Astronomy, told Space.com in an email. “We are interested in the origin of amino acids in general and their distribution in our galaxy.”

    alma
    The central region of the Milky Way can be seen above the antennas of the ALMA observatory in Chile.

    Scientists have previously found amino acids in meteorites that fell to Earth, and the composition of these chemicals suggested they had an interstellar origin. The researchers in this new study did not find amino acids, but their discovery adds an “additional piece of evidence that the amino acids found in meteorites could have been formed in the interstellar medium,” Belloche wrote.

    “The detection of a molecule with a branched carbon backbone in interstellar space, in a region where stars are being formed, is interesting because it shows that interstellar chemistry is indeed capable of producing molecules with such a complex, branched structure,” Belloche added.

    It was first suggested in the 1980s that branched molecules could form on the surface of dust grains in interstellar space. But this is the first time such compounds have been detected. What’s more, iso-propyl cyanide seemed to be plentiful — it was almost half as abundant of its more common sister variant in Sagittarius B2, the study found. This means that branched molecules could actually be quite ordinary in interstellar space, the researchers said.

    The research is detailed in the Sept. 26 edition of the journal Science.

    See the full article here.

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  • richardmitnick 2:33 pm on September 24, 2014 Permalink | Reply
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    From ALMA: “ALMA Extends Its Arms” 

    ESO ALMA Array
    ALMA

    Wednesday, 24 September 2014

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

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

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    Email: cblue@nrao.edu

    The Atacama Large Millimeter/submillimeter Array (ALMA) has successfully tested an antenna in the most extended configuration of the array yet, producing the longest baseline ever achieved by ALMA. This advance became possible once the first of ALMA’s three extended arms was successfully powered up for the first time, and opens up the possibility of greatly extending ALMA’s capabilities. With longer baselines, the ability of a radio telescope to see fine detail increases, allowing astronomers to uncover much more information about objects observed in the Universe.

    alma extend
    This image by ESO, no image credit

    truck
    ALMA transporter moving a distant antenna Lore, one of ALMA’s two tailor-made antenna transporters, made its first journey along the Pampa la Bola arm and relocated an antenna to a distant pad. Engineers had to design vehicles rugged and durable enough to carry the antennas safely through the hostile desert environment. | ALMA (ESO/NAOJ/NRAO), P. Carrillo Download image

    Lore, one of ALMA’s two tailor-made antenna transporters, made its first journey along the Pampa la Bola arm and for the first time relocated an antenna to a position seven kilometers away from its furthest neighbour. This marks a major new technical achievement in the Atacama Desert in Chile, at more than 5000 metres above sea level. This new baseline is more than four times longer than is currently available to the ALMA scientific community, and tests of even longer baselines are in progress.

    Catherine Vlahakis, Program Scientist for the ALMA Long Baseline Campaign says that: “successfully powering up an antenna for the first time over these long distances marks an important technical step towards increasing ALMA’s ability to see objects in the Universe in fine detail”.

    antenna
    A distant ALMA antenna This image shows an ALMA antenna on a distant pad in the Pampa la Bola branch, with Japanese ASTE and NANTEN2 telescopes in the background. | ALMA (ESO/NAOJ/NRAO), T. Sawada Download image

    Ed Fomalont, Lead Scientist for the ALMA Long Baseline Campaign, explains that “the combination of the signals from the antennas produces patterns called fringes. The fringes measured from the antenna seven kilometres away were as pure and strong as will be needed to obtain high quality images when additional antennas are moved to these long baselines.”

    Catherine Vlahakis, adds that “this is the first step in a process of moving several antennas out to these longer distances. Once the rest of the antennas are also in place we will be able to begin test observations of astronomical objects at higher angular resolution, and therefore in more exquisite detail, than ALMA has yet achieved.”

    Observations that will further test baselines as long as nearly 11 kilometers will continue over the next two months. If all goes as intended, this process will provide ALMA astronomers with the knowledge needed to offer long-baseline observations to the scientific community.

    See the full article here.

    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.

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  • richardmitnick 6:20 pm on September 22, 2014 Permalink | Reply
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    From ALMA: “ALMA Studies Infant Sun-like Solar System to Try and Catch the Wind” 

    ESO ALMA Array
    ALMA

    Monday, 22 September 2014

    Contacts

    Dr. Colette Salyk
    National Optical Astronomy Observatory
    950 N Cherry Ave, Tucson AZ 85719 USA
    E-mail: csalyk@noao.edu

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    Email: cblue@nrao.edu

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

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have studied a special kind of young star, a T Tauri star, to understand why some have disks that glow weirdly in infrared light while others shine in a more predictable fashion. The answer, researchers speculate, may be due to differences in the wind around these stars.

    tt

    T Tauri stars are the infant versions of stars like our Sun. They are relatively normal, medium size-stars that are surrounded by the raw materials to build both rocky and gaseous planets. Though nearly invisible in optical light, these disks shine in both infrared and millimeter-wavelength light.

    “The material in the disk of a T Tauri star usually, but not always, emits infrared radiation with a predictable energy distribution,” said Colette Salyk, an astronomer with the National Optical Astronomical Observatory (NOAO) and lead author on a paper published in the Astrophysical Journal, “some T Tauri stars, however, like to act up by emitting infrared radiation in unexpected ways.”

    To account for the different infrared signature around such similar stars, astronomers propose that winds may be emanating from within some T Tauri stars’ protoplanetary disks. These winds could have important implications for planet formation, potentially robbing the disk of some of the gas required for the formation of giant Jupiter-like planets, or stirring up the disk and causing the building blocks of planets to change location entirely. These winds have been predicted by astronomers, but have never been clearly detected.

    Using ALMA, Salyk and her colleagues looked for evidence of a possible wind in AS 205 N, a T Tauri star located 407 light-years away at the edge of a star-forming region in the constellation Ophiuchus, the Snake Bearer. This star seemed to exhibit the characteristically uneven infrared signature that had intrigued astronomers.

    With ALMA’s exceptional resolution and sensitivity, the researchers were able to study the distribution of carbon monoxide around the star. Carbon monoxide is an excellent tracer for the molecular gas that makes up stars and their planet-forming disks. These studies confirmed that there was indeed gas leaving the disk surface, as would be expected if a wind were present. The properties of the wind, however, did not exactly match expectations.

    This different between observations and expectations could be due to the fact that AS 205 N is actually part of a multiple star system – with a companion dubbed AS 205 S, that is itself a binary star.

    This multiple star arrangement may suggest that the gas is leaving the disk surface because it’s being pulled away by the binary companion star rather than ejected by a wind.

    “We are hoping these new ALMA observations help us better understand winds, but they have also left us with a new mystery,” said Salyk, “Are we seeing winds, or interactions with the companion star?”

    The study’s authors are not pessimistic, however. They plan to continue their research with more ALMA observations, targeting other unusual T Tauri stars, with and without companions, to see whether they show these same features.

    T Tauri stars are named after their prototype star, discovered in 1852 – the third star in the constellation Taurus whose brightness was found to vary erratically. At one point, some 4.5 billion years ago, our Sun was a T Tauri star.

    This work is published in the Astrophysical Journal: other authors include Klaus Pontoppidan, Space Telescope Science Institute; Stuartt Corder, Joint ALMA Observatory; Diego Muñoz, Center for Space Research, Department of Astronomy, Cornell University; and Ke Zhang and Geoffrey Blake, Division of Geological & Planetary Sciences, California Institute of Technology.

    See the full article here.

    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.

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