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  • richardmitnick 5:35 pm on December 17, 2014 Permalink | Reply
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    From ALMA: “‘Perfect Storm’ Suffocating Star Formation around a Supermassive Black Hole” 

    ESO ALMA Array
    ALMA

    Wednesday, 17 December 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
    E-mail: cblue@nrao.edu

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

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

    High-energy jets powered by supermassive black holes can blast away a galaxy’s star-forming fuel — resulting in so-called “red and dead” galaxies: those brimming with ancient red stars yet little or no hydrogen gas available to create new ones.

    Now astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that black holes don’t have to be nearly so powerful to shut down star formation. By observing the dust and gas at the center NGC 1266, a nearby lenticular galaxy with a relatively modest central black hole, the astronomers have detected a “perfect storm” of turbulence that is squelching star formation in a region that would otherwise be an ideal star factory.

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    NGC 1266

    This turbulence is stirred up by jets from the galaxy’s central black hole slamming into an incredibly dense envelope of gas. This dense region, which may be the result of a recent merger with another smaller galaxy, blocks nearly 98 percent of material propelled by the jets from escaping the galactic center.

    “Like an unstoppable force meeting an immovable object, the molecules in these jets meet so much resistance when they hit the surrounding dense gas that they are almost completely stopped in their tracks,” said Katherine Alatalo, an astronomer with the California Institute of Technology in Pasadena and lead author on a paper published in the Astrophysical Journal. This energetic collision produces powerful turbulence in the surrounding gas, disrupting the first critical stage of star formation. “So what we see is the most intense suppression of star formation ever observed,” noted Alatalo.

    Previous observations of NGC 1266 revealed a broad outflow of gas from the galactic center traveling up to 400 kilometers per second. Alatalo and her colleagues estimate that this outflow is as forceful as the simultaneous supernova explosion of 10,000 stars. The jets, though powerful enough to stir the gas, are not powerful enough to give it the velocity it needs to escape from the system.

    “Another way of looking at it is that the jets are injecting turbulence into the gas, preventing it from settling down, collapsing, and forming stars,” said National Radio Astronomy Observatory astronomer and co-author Mark Lacy.

    The region observed by ALMA contains about 400 million times the mass of our Sun in star-forming gas, which is 100 times more than is found in giant star-forming molecular clouds in our own Milky Way. Normally, gas this concentrated should be producing stars at a rate at least 50 times faster than the astronomers observed in this galaxy.

    Previously, astronomers believed that only extremely powerful quasars and radio galaxies contained black holes that were powerful enough to serve as a star-forming “on/off” switch.

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    A combined Hubble Space Telescope / ALMA image of NGC 1266. The ALMA data (orange) are shown in the central region. Credit: NASA/ESA Hubble; ALMA (NRAO/ESO/NAOJ)

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    “The usual assumption in the past has been that the jets needed to be powerful enough to eject the gas from the galaxy completely in order to be effective at stopping start formation,” said Lacy.

    To make this discovery, the astronomers first pinpointed the location of the far-infrared light being emitted by the galaxy. Normally, this light is associated with star formation and enables astronomers to detect regions where new stars are forming. In the case of NGC 1266, however, this light was coming from an extremely confined region of the galaxy. “This very small area was almost too small for the infrared light to be coming from star formation,” noted Alatalo.

    With ALMA’s exquisite sensitivity and resolution, and along with observations from CARMA (the Combined Array for Research in Millimeter-wave Astronomy), the astronomers were then able to trace the location of the very dense molecular gas at the galactic center. They found that the gas is surrounding this compact source of the far-infrared light.

    CARMA Array
    CARMA

    Under normal conditions, gas this dense would be forming stars at a very high rate. The dust embedded within this gas would then be heated by young stars and seen as a bright and extended source of infrared light. The small size and faintness of the infrared source in this galaxy suggests that NGC 1266 is instead choking on its own fuel, seemingly in defiance of the rules of star formation.

    The astronomers also speculate that there is a feedback mechanism at work in this region. Eventually, the black hole will calm down and the turbulence will subside so star-formation can begin anew. With this renewed star formation, however, comes greater motion in the dense gas, which then falls in on the black hole and reestablishes the jets, shutting down star formation once again.

    NGC 1266 is located approximately 100 million light-years away in the constellation Eridanus. Leticular galaxies are spiral galaxies, like our own Milky Way, but they have little interstellar gas available to form new stars.

    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 9:39 pm on December 11, 2014 Permalink | Reply
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    From ALMA: “ALMA detects Pluto-Size Objects Kicking-up Dust around Sun-Like Star” 

    ESO ALMA Array
    ALMA

    Thursday, 11 December 2014
    Luca Ricci
    Harvard-Smithsonian Center for Astrophysics
    Email: lucaricci83@gmail.com

    Nicolás Lira
    Education and Public Outreach Assistant
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6519
    Cell: +56 9 9445 7726
    Email: nlira@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
    E-mail: cblue@nrao.edu

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

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

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) may have detected the dusty hallmarks of an entire family of Pluto-size objects swarming around an adolescent version of our own Sun.

    By making detailed observations of the protoplanetary disk surrounding the star known as HD 107146, the astronomers detected an unexpected increase in the concentration of millimeter-size dust grains in the disk’s outer reaches. This surprising increase, which begins remarkably far — about 13 billion kilometers — from the host star, may be the result of Pluto-size planetesimals stirring up the region, causing smaller objects to collide and blast themselves apart.

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    ALMA image of the dust surrounding the star HD 107146. Dust in the outer reaches of the disk is thicker than in the inner regions, suggesting that a swarm of Pluto-size planetesimals is causing smaller objects to smash together. The dark ring-like structure in the middle portion of the disk may be evidence of a gap where a planet is sweeping its orbit clear of dust. Credit: L. Ricci ALMA (NRAO/NAOJ/ESO); B. Saxton (NRAO/AUI/NSF).

    The new ALMA data also hint at another intriguing feature in the outer reaches of the disk: a possible “dip” or depression in the dust about 1.2 billion kilometer wide, beginning approximately 2.5 times the distance of the Sun to Neptune from the central star. Though only suggested in these preliminary observations, this depression could be a gap in the disk, which would be indicative of an Earth-mass planet sweeping the area clear of debris. Such a feature would have important implications for the possible planet-like inhabitants of this disk and may suggest that Earth-size planets could form in an entirely new range of orbits than have ever been seen before.

    “ALMA is critical for the study of these systems that are transitioning from forming planets to having mature planet systems,” said ALMA Deputy Director and coauthor Stuartt Corder. “The material is very tenuous and the combination of sensitivity and resolution offered by ALMA not only makes details in these sorts of objects observable, it makes such observations routine.”

    The star HD 107146 is of particular interest to astronomers because it is in many ways a younger version of our own Sun. It also represents a period of transition from a solar system’s early life to its more mature, final stages where planets have finished forming and have settled into their billions-of-years-long orbits around their host star.

    “This system offers us the chance to study an intriguing time around a young, Sun-like star,” explained Corder. “We are possibly looking back in time here, back to when the Sun was about two percent of its current age.”

    The star HD 107146 is located approximately 90 light-years from Earth in the direction of the constellation Coma Berenices. It is approximately 100 million years old. Further observations with ALMA’s new long baseline, high resolution capabilities will shed more light on the dynamics and composition of this intriguing object. “At longer baselines, we expect to clearly determine the nature of the gap: is it created by a planet or not?” added Corder.

    Additional authors on the paper include John M. Carpenter and B. Fu, Caltech; A. M. Hughes, Wesleyan University; and Andrea Isella, Rice University.

    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 9:35 am on December 4, 2014 Permalink | Reply
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    From ALMA: “ALMA Identifies Gas Spirals as a Nursery of Twin Stars” 

    ESO ALMA Array
    ALMA

    Thursday, 04 December 2014
    Shigehisa Takakuwa
    Associate Research Fellow, Institute of Astronomy Astrophysics,
    Academia Sinica
    Taipei, Taiwan
    Email: takakuwa@asiaa.sinica.edu.tw
    Tel: +886-2-2366-5395

    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

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

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

    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

    With new Atacama Large Millimeter/submillimeter Array (ALMA) observations, astronomers led by Shigehisa Takakuwa, Associate Research Fellow at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taiwan, have found spiral arms of molecular gas and dust around “baby twin” stars. Gas motions supplying materials to the twin were also identified. These results unveil for the first time, the mechanism of the birth and growth of binary stars, which are ubiquitous throughout the Universe. The study was published on November 20 in The Astrophysical Journal.

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    Fig 1. Gas and dust disks around L1551 NE spotted by ALMA. Credit: ALMA (ESO/NAOJ/NRAO)/Takakuwa et al.

    Stars form in interstellar clouds of molecular gas and dust. Previous studies of star formation focused primarily on single stars like the Sun, and a standard picture of single star formation has been established. According to this picture, a dense gas condensation in an interstellar cloud collapses gravitationally to form a single protostar at the center. Previous observations have found such collapsing gas motions feeding material toward the central protostars.

    Compared to single star formation, our understanding of binary star formation has been limited, even though more than half of stars with a mass similar to that of the Sun are known to be binaries. It is thus crucial to observe the physical mechanism of binary formation to obtain a more comprehensive understanding of star formation. Theory suggests that a disk surrounding a young binary will feed material to the central “baby twin” in order for them to grow. While recent observations have found such disks (known as “circumbinary disks“), it was not possible to image the structure and gas motions because of the insufficient imaging resolution and sensitivity.

    2
    Fig 2. Comparison of the disks in simulation and observation. The right panel shows the disk image simulated with ATERUI, and the left panel the real ALMA image. Credit: ALMA (ESO/NAOJ/NRAO)/Takakuwa et al.

    The research team, led by Shigehisa Takakuwa, used the ALMA telescope to observe the baby-twin star L1551 NE [1], located in the constellation of Taurus at a distance of 460 light years, with a 1.6 times better imaging resolution and a 6 times better sensitivity than those of their previous observations with the SubMillimeter Array (SMA).

    Submillimeter Array Hawaii SAO
    CfA Submillimeter Array

    They used the emission from dust at a wavelength of 0.9mm to trace the distribution of interstellar material, and emission from carbon monoxide to study gas motions using the Doppler Effect. They found gas associated with each binary star (the two central components can be seen in Figure 1), and a disk surrounding both stars, the circumbinary disk, with a radius of 300 au. The radius corresponds to 10 times the orbital radius of Neptune in our solar system. For the first time, they succeeded in imaging the detailed structure of the circumbinary disk, and found that it consists of a southern U-shaped feature with northern extensions pointing to the northwest and the northeast (Figure 1).

    To understand these newly-identified features, the research team constructed a theoretical model of binary formation in L1551 NE, shown in Figure 2 (right, see also the attached movie), using the supercomputer, “ATERUI” at the National Astronomical Observatory of Japan (NAOJ) [2]. As shown in Figure 2, the southern U-shaped feature and northern emission protrusions observed with ALMA can be reproduced with a pair of spiral arms stemming from each of the baby twins. The research team also investigated the gas motion as seen in carbon monoxide, and found the spiral arms to be rotating faster than the regions between the arms. These inter-arm regions show gas falling toward the central baby twins. This is believed to be the ongoing feeding process of the baby twins. These results show that the twins “shake” the surrounding circumbinary disk and induce the falling gas motion. “Our high-resolution ALMA observation has unveiled live images of the growth of the baby twins for the first time”, said Takakuwa.

    Tomoaki Matsumoto, a professor at Hosei University, who constructed the theoretical model with the supercomputer, said, “The ALMA results match with our theoretical prediction remarkably accurately” [3]. Kazuya Saigo, co-principal investigator along with Takakuwa, explained, “We succeeded in unveiling the structure and motion in the circumbinary disk with high accuracy, because of the high resolution and sensitivity of ALMA. Combining these high-resolution ALMA observations with thorough numerical simulations using a supercomputer will become more and more important, and can be regarded as an upcoming research trend”.

    Notes:

    [1] The mass of each twin of L1551 NE is 0.67 and 0.13 times the mass of the Sun, and their separation is 145 au (astronomical unit; 1 au is the distance between the Sun and the Earth, approximately 150 million km).

    [2] The supercomputer ATERUI (Cray XC30), operated by NAOJ Center for Computational Astrophysics, is the fastest one dedicated for astrophysics research.

    NAOJ Cray ATERUI

    [3] NAOJ’s Subaru Telescope found a spiral structure around a more evolved binary system SR24. The stars in SR24 are close to the final stage of their growth and the gas envelope has almost dissipated, whereas the twin stars in L1551 NE are in the very early, active stage of their growth. The ALMA observation shows that the spiral structure plays an important role in this very early phase of binary formation.

    NAOJ Subaru Telescope
    NAOJ Subaru Telescope interior
    NAOJ Subaru

    Reference:

    First Direct Imaging of a Young Binary System http://subarutelescope.org/Pressrelease/2009/11/19/index.html

    These observational results were published in The Astrophysical Journal as Takakuwa et al. Angular Momentum Exchange by Gravitational Torques and Infall in the Circumbinary Disk of the Protostellar System L1551 NE in November 2014.

    The complete list of authors is: Shigehisa Takakuwa (ASIAA), Masao Saito (NAOJ/SOKENDAI (The Graduate University for Advanced Studies)),Kazuya Saigo (NAOJ), Tomoaki Matsumoto (Hosei Univ.), Jeremy Lim (Univ. of Hong-Kong), Tomoyuki Hanawa (Chiba Univ.), and Paul T. P. Ho (ASIAA).

    The research was supported by research grants from the Ministry of Science and Technology of Taiwan (MOST 102-2119-M-001-012-MY3), GRF grants of the Government of the Hong Kong SAR under HKU 703512P and the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Numbers 24244017, 23540270.

    See the full article, with video, here.

    Please help promote STEM in your local schools.

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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 8:06 pm on November 26, 2014 Permalink | Reply
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    From ESO: “ESOcast 69: Revolutionary ALMA Image Reveals Planetary Genesis “ 


    European Southern Observatory

    ESOcast 69 presents the result of the latest ALMA observations, which reveal extraordinarily fine detail that has never been seen before in the planet-forming disc around the young star HL Tauri.

    This revolutionary image is the result of the first observations that have used ALMA with its antennas at close to the widest configuration possible. As a result, it is the sharpest picture ever made at submillimetre wavelengths.

    Watch, enjoy, learn.

    See the full article here.

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  • richardmitnick 9:13 pm on November 24, 2014 Permalink | Reply
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    From ALMA via ESO: “Seeing into the Heart of Mira A and its Partner” 

    ALMA Array
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    European Southern Observatory

    Studying red giant stars tells astronomers about the future of the Sun — and about how previous generations of stars spread the elements needed for life across the Universe. One of the most famous red giants in the sky is called Mira A, part of the binary system Mira which lies about 400 light-years from Earth. In this image ALMA reveals Mira’s secret life.

    Mira A is an old star, already starting to throw out the products of its life’s work into space for recycling. Mira A’s companion, known as Mira B, orbits it at twice the distance from the Sun to Neptune.

    m
    ESO/S. Ramstedt (Uppsala University, Sweden) & W. Vlemmings (Chalmers University of Technology, Sweden)

    Mira A is known to have a slow wind which gently moulds the surrounding material. ALMA has now confirmed that Mira’s companion is a very different kind of star, with a very different wind. Mira B is a hot, dense white dwarf with a fierce and fast stellar wind.

    New observations show how the winds from the two stars have created a fascinating, beautiful and complex nebula. The remarkable heart-shaped bubble at the centre is created by Mira B’s energetic wind inside Mira A’s more relaxed outflow. The heart, which formed some time in the last 400 years or so, and the rest of the gas surrounding the pair show that they have long been building this strange and beautiful environment together.

    By looking at stars like Mira A and Mira B scientists hope to discover how our galaxy’s double stars differ from single stars in how they give back what they have created to the Milky Way’s stellar ecosystem. Despite their distance from one another, Mira A and its companion have had a strong effect on one another and demonstrate how double stars can influence their environments and leave clues for scientists to decipher.

    Other old and dying stars also have bizarre surroundings, as astronomers have seen using both ALMA and other telescopes. But it’s not always clear whether the stars are single, like the Sun, or double, like Mira. Mira A, its mysterious partner and their heart-shaped bubble are all part of this story.

    The new observations of Mira A and its partner are presented in this paper.

    See the full article here.

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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.

    Please help promote STEM in your local schools.

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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
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    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.

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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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