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  • richardmitnick 12:05 pm on August 17, 2017 Permalink | Reply
    Tags: ALMA, , , , , , Researchers at ALMA study the effects of working at high altitude   

    From ALMA: “Researchers at ALMA study the effects of working at high altitude” 

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

    17 August, 2017

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    nicolas.lira@alma.cl

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    An international team of doctors and researchers conducted a study at the Atacama Large Millimeter/submillimeter Array (ALMA) to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the Operations Support Facility (OSF) and the Array Operations Site (AOS) at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. The first results of these studies are being made available to the scientific community (see posters) and will soon be published.

    Canadian, Swiss, and Chilean experts met at ALMA in April 2016 to examine workers who volunteered for the study, separating those who suffer from chronic illnesses such as hypertension or obesity from healthy workers in order to compare and understand the effects of hypoxia. Over the course of six weeks, doctors examined their cognitive skills, sleep quality, breathing patterns, blood flow to the brain, and hemodynamic changes between the heart and lungs.

    For Dr. Marc Poulin from the University of Calgary, Canada, who forms part of this study, “The working conditions at ALMA are ideal for our research. It has high quality infrastructure and is a true natural laboratory due to its high altitude.”

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    An international team of doctors and researchers conducted a study at ALMA to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the OSF and the AOS at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. Credit: Iván López – ALMA (NRAO/NAOJ/ESO)

    Most of the workers at the observatory live in cities located at low altitudes, and work 8×6 shifts (8 days of work followed by 6 days off) at the ALMA OSF. The camp where the workers sleep is located here, as well as the laboratories, workshops, offices and antenna control room. Some workers have to ascend to the ALMA AOS at 5,000 meters, where they work with the antennas and correlator that synchronizes their signals. It is at this higher altitude that some staff experience intermittent hypoxia.

    The purpose of this study is to understand the long-term effects on workers’ performance, health, and safety from ongoing or intermittent exposure to hypoxia. This study is meant to optimize treatments that would help workers operate at altitude. It also may lead to new treatments from the lessons learned through this study in development.

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    “We are very happy about this study, as it gives us an objective database of the effects of hypoxia in workers and helps adapt the risk prevention program to real conditions, in order to improve the quality of life of all staff,” says Iván López, ALMA Risk Prevention, Health, Environment and Safety Manager.

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    An international team of doctors and researchers conducted a study at ALMA to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the OSF and the AOS at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. Credit: Iván López – ALMA (NRAO/NAOJ/ESO)

    Early results from these studies suggest that intermittent and/or regular exposure to high altitudes may have a negative effect on psychomotor alertness, which is especially evident in those who work on tasks that require a high level of concentration, such as those found in mining and astronomical observatories. It also has bearing on athletes performing at high altitude.

    These studies also indicate that there is an alteration in workers’ sleep quality, although acclimatization would reduce these effects after a few days of exposure. Cognitive abilities would also be affected at extreme altitude exposure (5,050 meters above sea level), especially cognitive abilities and, to a much lesser extent, executive capacity. These effects would also be partially reduced as workers are acclimatized after a few days.

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    Among the measures taken by ALMA to reduce the effects of hypoxia are the mandatory use of portable medical oxygen for all workers performing tasks over an altitude of 3000 meters, permanent oxygenation of the technical building located at an altitude of 5000 meters, and constant on-site monitoring by the observatory’s medical team. In addition, new strategies are being developed that include a special diet and exercise program.

    See the full article here .

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

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

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

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  • richardmitnick 5:47 pm on August 2, 2017 Permalink | Reply
    Tags: ALMA, , , , , galaxy cluster XMMXCS J2215.9–1738, , Running Out of Gas: Gas Loss Puts Breaks on Stellar Baby Boom   

    From ALMA: “Running Out of Gas: Gas Loss Puts Breaks on Stellar Baby Boom” 

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

    2 August, 2017

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    nicolas.lira@alma.cl

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

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

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

    1
    No image caption or credit

    Astronomers observed a galaxy cluster 9.4 billion light-years away using the ALMA radio telescope array and found evidence that hot gas strips away the cold gas in the member galaxies. Since cold gas is the material for forming new stars, removing the cold gas inhibits star formation. This result is key to understanding the declining birthrate of stars throughout the history of the Universe and the evolutionary process of galaxy clusters.

    Understanding the history of star formation in the Universe is a central theme in modern astronomy. Various observations have shown that the star formation activity has varied through the 13.8 billion-year history of the Universe. The stellar birth rate peaked around 10 billion years ago and has declined steadily since then. However, the cause of the declining stellar birth rate is still not well understood.

    “Aiming to investigate what suppresses the star formation activity, we focused on the environment around the galaxies,” said Masao Hayashi at the National Astronomical Observatory of Japan (NAOJ).

    Hayashi and his colleagues observed the galaxy cluster XMMXCS J2215.9–1738 located 9.4 billion light-years away [1] with the Atacama Large Millimeter/submillimeter Array (ALMA). Because it takes time for the light from distant objects to reach us, observing far-away galaxies shows us what the Universe looked like when the light was emitted. In this case, the light from XMMXCS J2215.9-1738 was emitted 9.4 billion years ago, which is around the time that the stellar birth rate peaked. In fact, previous observations with NAOJ’s Subaru Telescope revealed that many of the galaxies in the cluster are actively forming stars.

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    ALMA detected radio signals emitted from carbon monoxide gas in 17 of the galaxies in the cluster. This is a record-high number for the detection of gas-rich galaxies at such a distance. Interestingly, the gas-rich galaxies detected with ALMA are located towards the outer part of the galaxy cluster, not in the center. This is the first time ever that such a location differentiation has been found in a galaxy cluster 10 billion light-years away.

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    Galaxy cluster XMMXCS J2215.9–1738 observed with ALMA and the Hubble Space Telescope. Gas rich galaxies detected with ALMA are shown in red and marked with circles. Most gas rich galaxies are located in the outer part, not the center, of the galaxy cluster (around the center of the image). Credit: ALMA (ESO/NAOJ/NRAO), Hayashi et al., the NASA/ESA Hubble Space Telescope

    NASA/ESA Hubble Telescope

    The team assumes that the gas-rich galaxies detected with ALMA are in an intermediate step in the process of becoming members of the cluster. As new member galaxies pass through the hot gas filling the cluster, cold gas in the galaxies is stripped away by the hot gas. Active star formation consumes what little gas survives in the galaxies. As the cold gas needed to make stars run out, star formation stops.

    Actually, there are some galaxies with active star formation at the central part of the cluster. The team suggests that they are rather evolved, old members of the cluster consuming the last of their gas to form stars.

    “Recent observational and theoretical studies show that the distribution of gas is key to understanding the evolution of galaxies,” explains Hayashi. “Our observations provide robust statistics showing that a number of gas-rich galaxies are located in the outer part of a galaxy cluster. With this result, we have opened a future path for revealing the evolutionary process of galaxies in galaxy clusters.”

    Notes

    [1] The measured redshift of the galaxy cluster is z=1.46. A calculation based on the latest cosmological parameters measured with Planck (H0=67.3 km/s/Mpc, Ωm=0.315, Λ=0.685: Planck 2013 Results) yields the distance of 9.4 billion light-years. Please refer to “Expressing the distance to remote objects” for the details.

    Additional Information

    These observation results were published as Hayashi et al. Evolutionary Phases of Gas-rich Galaxies in a Galaxy Cluster at z = 1.46 in The Astrophysical Journal Letters in May 2017.

    The research team members are: Masao Hayashi (National Astronomical Observatory of Japan), Tadayuki Kodama (NAOJ/SOKENDAI/Tohoku University), Kotaro Kohno (The University of Tokyo), Yuki Yamaguchi (The University of Tokyo), Ken-ichi Tadaki (NAOJ/Max Planck Institute for Extraterrestrial Physics), Bunyo Hatsukade (The University of Tokyo), Yusei Koyama (NAOJ/SOKENDAI), Rhythm Shimakawa (NAOJ/University of California), Yoichi Tamura (The University of Tokyo/Nagoya University), and Tomoko L. Suzuki (NAOJ)

    This research was supported by Grants-in-Aid from the Japan Society for the Promotion of Science and the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 26707006, 21340045, 24244015, 15H02073, 25247019).

    See the full article here .

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

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

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

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  • richardmitnick 2:13 pm on July 28, 2017 Permalink | Reply
    Tags: ALMA, , , , ,   

    From ALMA: “ALMA Confirms Complex Chemistry in Titan’s Atmosphere: Saturn’s Moon Offers Glimpse of Earth’s Primordial Past” 

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

    28 July, 2017

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    nicolas.lira@alma.cl

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

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

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

    Saturn’s frigid moon Titan has a curious atmosphere. In addition to a hazy mixture of nitrogen and hydrocarbons like methane and ethane, Titan’s atmosphere also contains an array of more complex organic molecules, including vinyl cyanide, which astronomers recently uncovered in archival ALMA data. Under the right conditions, like those found on the surface of Titan, vinyl cyanide may naturally coalesce into microscopic spheres resembling cell membranes.

    Saturn’s largest moon, Titan, is one of our solar system’s most intriguing and Earth-like bodies. It is nearly as large as Mars and has a hazy atmosphere made up mostly of nitrogen with a smattering of organic, carbon-based molecules, including methane (CH4) and ethane (C2H6). Planetary scientists theorize that this chemical make-up is similar to Earth’s primordial atmosphere.

    The conditions on Titan, however, are not conducive to the formation of life as we know it; it’s simply too cold. At ten times the distance from the Earth to the sun, Titan is so cold that liquid methane rains onto its solid icy surface, forming rivers, lakes, and seas.

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    Archival ALMA data have confirmed that molecules of vinyl cyanide reside in the atmosphere of Titan, Saturn’s largest moon. Titan is shown in an optical (atmosphere) infrared (surface) composite from NASA’s Cassini spacecraft. In a liquid methane environment, vinyl cyanide may form membranes. Credit: B. Saxton (NRAO/AUI/NSF); NASA.

    These pools of hydrocarbons, however, create a unique environment that may help molecules of vinyl cyanide (C2H3CN) link together to form membranes, features resembling the lipid-based cell membranes of living organisms on Earth.

    Astronomers using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), which was collected over a series of observations from February to May 2014, have found compelling evidence that molecules of vinyl cyanide are indeed present on Titan and in significant quantities.

    “The presence of vinyl cyanide in an environment with liquid methane suggests the intriguing possibility of chemical processes that are analogous to those important for life on Earth,” said Maureen Palmer, a researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author on a paper published in Science Advances.

    Previous studies by NASA’s Cassini spacecraft, as well as laboratory simulations of Titan’s atmosphere, inferred the likely presence of vinyl cyanide on Titan, but it took ALMA to make a definitive detection.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    By reviewing the archival data, Palmer and her colleagues found three distinct signals – spikes in the millimeter-wavelength spectrum – that correspond to vinyl cyanide. These telltale signatures originated at least 200 kilometers above the surface of Titan.

    Titan’s atmosphere is a veritable chemical factory, harnessing the light of the sun and the energy from fast-moving particles that orbit around Saturn to convert simple organic molecules into larger, more complex chemicals.

    “As our knowledge of Titan’s chemistry grows, it becomes increasingly apparent that complex molecules arise naturally in environments similar to those found on the early Earth, but there are important differences,” said Martin Cordiner, also with NASA’s Goddard Space Flight Center and a co-author on the paper.

    For example, Titan is much colder than Earth at any period in its history. Titan averages about 95 kelvins (-290 degrees Fahrenheit), so water at its surface remains frozen. Geologic evidence also suggests that the early Earth had high concentrations of carbon dioxide (CO2); Titan does not. Earth’s rocky surface was also frenetically active, with extensive volcanism and routine asteroid impacts, which would have affected the evolution of our atmosphere. In comparison, Titan’s icy crust appears quite docile.

    “We are continuing to use ALMA to make further observations of Titan’s atmosphere,” concluded Conor Nixon, also with NASA’s Goddard Space Flight Center and a co-author on the paper. “We are looking for new and more complex organic chemicals as well as studying this moon’s atmospheric circulation patterns. In the future, higher-resolution studies will shed more light on this intriguing world and hopefully give us new insights into Titan’s potential for prebiotic chemistry.”

    Additional Information

    These results are in a paper titled ALMA Detection and Astrobiological Potential of Vinyl Cyanide on Titan, M. Palmer et al., appearing in Science Advances [see above].

    See the full article here .

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

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

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

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  • richardmitnick 5:08 pm on July 17, 2017 Permalink | Reply
    Tags: ALMA, , , , , , , ,   

    From Webb: “Birth of Stars & Protoplanetary Systems” 

    NASA Webb Header

    NASA Webb Telescope

    James Webb Space Telescope

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    The Pillars of Creation in the Eagle Nebula captured in visible light by Hubble. Stellar nurseries are hidden within the towers of dust and gas. Credit: NASA/ESA/Hubble Heritage Team (STScI/AURA)/J. Hester, P. Scowen (Arizona State U.)

    Inside the Pillars of Creation

    While this image is spectacular, there are actually stars that Hubble can’t see inside those pillars of dust. And that’s because the visible light emitted by those stars is being obscured by the dust. But what if we used a telescope sensitive to infrared light to look at this nebula?

    The next image is another Hubble view, but this time in near-infrared. In the infrared more structure within the dust clouds is revealed and hidden stars have now become apparent. (And if Hubble, which is optimized for visible light, can capture a near-infrared image like this, imagine what JWST, which is optimized for near-infrared and 100x more powerful than Hubble, will do!)

    Another nebula, the “Mystic Mountains” of the Carina Nebula, shown in two Hubble images, one in visible light (left) and one in infrared (right).
    In the infrared image, we can see more stars that just weren’t visible before. Why is this?

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    The Pillars of Creation in the Eagle Nebula captured in infrared light by Hubble. The light from young stars being formed pierce the clouds of dust and gas in the infrared. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

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    Comparison of the Carina Nebula in visible light (left) and infrared (left), both images by Hubble. Credit: NASA/ESA/M. Livio & Hubble 20th Anniversary Team (STScI)

    How Do Infrared Cameras Work?

    We can try a thought experiment. What if you were to put your arm into a garbage bag? Your arm is hidden. Invisible.

    But what if you looked at your arm and the garbage bag with an infrared camera? Remember that infrared light is essentially heat. And that while your eyes may not be able to pick up the warmth of your arm underneath the cooler plastic of the bag, an infrared camera can. An infrared camera can see right through the bag!

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    ALMA image of the young star HL Tau and its protoplanetary disk. This best image ever of planet formation reveals multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas. Credit: ALMA (NRAO/ESO/NAOJ); C. Brogan, B. Saxton (NRAO/AUI/NSF)

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

    The Dusty Cocoons of Star and Planet Formation

    JWST’s amazing imaging and spectroscopy capabilities will allow us to study stars as they are forming in their dusty cocoons. Additionally, it will be able to image disks of heated material around these young stars, which can indicate the beginnings of planetary systems, and study organic molecules that are important for life to develop.

    _________________________________________________________________
    Key Questions

    JWST will address several key questions to help us unravel the story of the star and planet formation:

    How do clouds of gas and dust collapse to form stars?
    Why do most stars form in groups?
    Exactly how do planetary systems form?
    How do stars evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets?

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    Infrared Spitzer image of a star-forming region. Credit: NASA/JPL-Caltech/ Harvard-Smithsonian CfA

    NASA/Spitzer Telescope

    JWST’s Role in Answering These Questions

    To unravel the birth and early evolution of stars and planets, we need to be able to peer into the hearts of dense and dusty cloud cores where star formation begins. These regions cannot be observed at visible light wavelengths as the dust would make such regions opaque and must be observed at infrared wavelengths.

    Stars, like our Sun, can be thought of as “basic particles” of the Universe, just as atoms are “basic particles” of matter. Groups of stars make up galaxies, while planets and ultimately life arise around stars. Although stars have been the main topic of astronomy for thousands of years, we have begun to understand them in detail only in recent times through the advent of powerful telescopes and computers.

    A hundred years ago, scientists did not know that stars are powered by nuclear fusion, and 50 years ago they did not know that stars are continually forming in the Universe. Researchers still do not know the details of how clouds of gas and dust collapse to form stars, or why most stars form in groups, or exactly how planetary systems form. Young stars within a star-forming region interact with each other in complex ways. The details of how they evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets remains to be determined through a combination of observation and theory.

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    The stages of solar system formation. Credit: Shu et al. 1987

    The stages of solar system formation are illustrated to the right: starting with a protostar embedded in a gas cloud (upper left of diagram), to an early star with a circumstellar disk (upper right), to a star surrounded by small “planetesimals” which are starting to clump together (lower left) to a solar system like ours today.

    The continual discovery of new and unusual planetary systems has made scientists re-think their ideas and theories about how planets are formed. Scientists realize that to get a better understanding of how planets form, they need to have more observations of planets around young stars, and more observations of leftover debris around stars, which can come together and form planets.

    _________________________________________________________________

    Related Content
    More Comparison Images

    Here’s is another stunning comparison of visible versus infrared light views of the same object – the gorgeous Horsehead Nebula:

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    The Horsehead Nebula in visible light, captured by the Canada-France Hawaii Telescope. Credit: NASA

    Visible Light Horsehead Nebula


    CFHT Telescope, Maunakea, Hawaii, USA

    Infrared Light Horsehead Nebula

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    The Horsehead Nebula in infrared light, captured by the Hubble Space Telescope. Credit: NASA/Space Telescope Science Institute (STScI)

    NASA/ESA Hubble Telescope

    Related Video

    This video shows how JWST will peer inside dusty knots where the youngest stars and planets are forming.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

    Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

    NASA image

    ESA50 Logo large

    Canadian Space Agency

     
  • richardmitnick 12:13 pm on July 15, 2017 Permalink | Reply
    Tags: ALMA, Angular momentum, , , , , Elliptical galaxies, , , Shedding light on galaxies' rotation secrets,   

    From EurekaAlert: “Shedding light on galaxies’ rotation secrets” 

    eurekaalert-bloc

    EurekaAlert

    13-Jul-2017

    Media Contact
    Donato Ramani
    ramani@sissa.it
    39-342-802-2237
    http://www.sissa.it/

    Spiral galaxies are strongly rotating whereas the rotation velocity of ellipticals is much lower. A new study investigates the reasons of such a dichotomy revealing that it is imprinted at formation.

    Scuola Internazionale Superiore di Studi Avanzati

    1
    Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a difference?
    Credit Wikimedia Common.

    The dichotomy concerns the so-called angular momentum (per unit mass), that in physics is a measure of size and rotation velocity. Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a difference? An international research team investigated the issue in a study just published in the Astrophysical Journal. The team was led by SISSA Ph.D. student JingJing Shi under the supervision of Prof. Andrea Lapi and Luigi Danese, and in collaboration with Prof. Huiyuan Wang from USTC (Hefei) and Dr. Claudia Mancuso from IRA-INAF (Bologna). The researchers inferred from observations the amount of gas fallen into the central region of a developing galaxy, where most of the star formation takes places.

    The outcome is that in elliptical galaxies only about 40% of the available gas fell into that central region. More relevantly, this gas fueling star formation was characterized by a rather low angular momentum since the very beginning. This is in stark contrast with the conditions found in spirals, where most of the gas ending up in stars had an angular momentum appreciably higher. In this vein, the researchers have traced back the dichotomy in the angular momentum of spiral and elliptical galaxies to their different formation history. Elliptical galaxies formed most of their stars in a fast collapse where angular momentum is dissipated. This process is likely stopped early on by powerful gas outflows from supernova explosions, stellar winds and possibly even from the central supermassive black hole. For spirals, on the other hand, the gas infelt slowly conserving its angular momentum and stars formed steadily along a timescale comparable to the age of the Universe.

    “Till recent years, in the paradigm of galaxy formation and evolution, elliptical galaxies were thought to have formed by the merging of stellar disks in the distant Universe. Along this line, their angular momentum was thought to be the result of dissipative processes during such merging events” say the researchers. Recently, this paradigm had been challenged by far-infrared/sub-millimeter observations brought about by the advent of space observatories like Herschel and ground based interferometers like the Atacama Large Millimeter Array (ALMA).

    ESA/Herschel spacecraft

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

    These observations have the power of penetrating through interstellar dust and so to unveil the star formation processes in the very distant, dusty galaxies, that constituted the progenitors of local ellipticals. “The net outcome from these observations is that the stars populating present-day ellipticals are mainly formed in a fast dissipative collapse in the central regions of dusty starforming galaxies. After a short timescale of less than 1 billion years the star formation has been quenched by powerful gas outflows”. Despite this change of perspective, the origin of the low angular momentum observed in local ellipticals still remained unclear.

    “This study reconciles the low angular momentum observed in present-day ellipticals with the new paradigm emerging from Herschel and ALMA observations of their progenitors” conclude the scientists. “We demonstrated that the low angular momentum of ellipticals is mainly originated by nature in the central regions during the early galaxy formation process, and not nurtured substantially by the environment via merging events, as envisaged in previous theories”.

    See the full article here .

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    EurekAlert!, the premier online news source focusing on science, health, medicine and technology, is a free service for reporters worldwide.

    Since 1996, EurekAlert! has served as the leading destination for scientific organizations seeking to disseminate news to reporters and the public. Today, thousands of reporters around the globe rely on EurekAlert! as a source of ideas, background information, and advance word on breaking news stories.

    More than 1,000 peer-reviewed journals, universities, medical centers, government agencies and public relations firms have used EurekAlert! to distribute their news. EurekAlert! is an authoritative and comprehensive research news source for journalists all over the world.

     
  • richardmitnick 1:52 pm on July 10, 2017 Permalink | Reply
    Tags: , ALMA, , , , circumplanetary disk new simulations, , Exploring Disks Around Planets   

    From AAS NOVA: “Exploring Disks Around Planets” 

    AASNOVA

    American Astronomical Society

    10 July 2017
    Susanna Kohler

    1
    A 3-Jupiter-mass giant planet and its circumplanetary disk carve a gap in the circumstellar disk in this radius v. azimuth plot from a computer simulation. [Adapted from Szulágyi 2017]

    Giant planets are thought to form in circumstellar disks surrounding young stars, but material may also accrete into a smaller disk around the planet. We’ve never detected one of these circumplanetary disks before — but thanks to new simulations, we now have a better idea of what to look for.

    Elusive Disks

    2
    Image from previous work simulating a Jupiter-mass planet forming inside a circumstellar disk. The planet has its own circumplanetary disk of accreted material. [Frédéric Masset]

    In the formation of giant planets, we think the final phase consists of accretion onto the planet from a disk that surrounds it. This circumplanetary disk is important to understand, since it both regulates the late gas accretion and forms the birthplace of future satellites of the planet.

    We’ve yet to detect a circumplanetary disk thus far, because the resolution needed to spot one has been out of reach. Now, however, we’re entering an era where the disk and its kinematics may be observable with high-powered telescopes (like the Atacama Large Millimeter Array [ALMA]).

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

    To prepare for such observations, we need models that predict the basic characteristics of these disks — like the mass, temperature, and kinematic properties. Now a researcher at the ETH Zürich Institute for Astronomy in Switzerland, Judit Szulágyi, has worked toward this goal.

    Simulating Cooling

    Szulágyi performs a series of 3D global radiative hydrodynamic simulations of 1, 3, 5, and 10 Jupiter-mass (MJ) giant planets and their surrounding circumplanetary disks, embedded within the larger circumstellar disk around the central star.

    3
    Density (left column), temperature (center), and normalized angular momentum (right) for a 1 MJ planet over temperatures cooling from 10,000 K (top) to 1,000 K (bottom). At high temperatures, a spherical circumplanetary envelope surrounds the planet, but as the planet cools, the envelope transitions around 6–4,000 K to a flattened disk. [Szulágyi 2017]

    This work explores the effects of different planet temperatures and masses on the properties of the disks. Szulágyi specifically examines a range of planetary temperatures between 10,000 K and 1,000 K for the 1 MJ planet. Since the planet cools as it radiates away its formation heat, the different temperatures represent an evolutionary sequence over time.

    Predicted Characteristics

    Szulágyi’s work produced a number of intriguing observations, including the following:

    For the 1 MJ planet, a spherical circumplanetary envelope forms at high temperatures, flattening into a disk as the planet cools. Higher-mass planets form disks even at high temperatures.
    The disk has a steep temperature profile from inside to outside, and the whole disk is too hot for water to remain frozen. This suggests that satellites couldn’t form in the disk earlier than 1 Myr after the planet birth. The outskirts of the disk cool first as the planet cools, indicating that satellites may eventually form in these outer parts and then migrate inward.
    The planets open gaps in the circumstellar disk as they orbit. As a planet radiates away its formation heat, the gap it opens becomes deeper and wider (though this is a small effect). For high-mass planets (>5 MJ), the gap eccentricity increases, which creates a hostile environment for satellite formation.

    Szulágyi discusses a number of features of these disks that we can plan to search for in the future with our increasing telescope power — including signatures in direct imaging and observations of their kinematics. The results from these simulations will help us both to detect these circumplanetary disks and to understand our observations when we do. These future observations will then allow us to learn about late-stage giant-planet formation as well as the formation of their satellites.

    Citation

    J. Szulágyi 2017 ApJ 842 103. doi:10.3847/1538-4357/aa7515

    Related Journal Articles
    For further references with links see the full article.

    See the full article here .

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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 11:34 am on July 10, 2017 Permalink | Reply
    Tags: ALMA, , , , , , , SN1987A in 3-D   

    From ALMA: “Heart of an Exploded Star Observed in 3-D” 

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

    10 July, 2017

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    nicolas.lira@alma.cl

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

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

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

    1
    This artist’s illustration of Supernova 1987A reveals the cold, inner regions of the exploded star’s remnants (red) where tremendous amounts of dust were detected and imaged by ALMA. This inner region is contrasted with the outer shell (blue), where the energy from the supernova is colliding (green) with the envelope of gas ejected from the star prior to its powerful detonation. Credit: A. Angelich; NRAO/AUI/NSF

    Deep inside the remains of an exploded star lies a twisted knot of newly minted molecules and dust forged in the cooling aftermath of a supernova first detected in 1987. Using ALMA, astronomers mapped the location of these new molecules to create a high-resolution 3-D image of this “dust factory,” providing important insights into the relationship between a young supernova remnant and its home galaxy.

    Supernovas — the violent ending of the brief but brilliant lives of massive stars — are among the universe’s most cataclysmic events. Though supernovas mark the death of stars, they also trigger the birth of new elements and the formation of molecules that fill the universe.

    In February of 1987, astronomers witnessed one of these events unfold inside the Large Magellanic Cloud, a tiny dwarf galaxy in the suburbs of the Milky Way approximately 163,000 light-years from Earth.

    Over the next 30 years, observations of the remnant of that explosion revealed never-before-seen details about the death of stars and how atoms created in those stars — like carbon, oxygen, and nitrogen — spill out into space and combine to form new molecules and dust. These microscopic particles may eventually find their way into future generations of stars and planets.

    2
    Remnant of Supernova 1987A as seen by ALMA. Purple area indicates emission from SiO molecules. Yellow area is emission from CO molecules. The blue ring is actual Hubble data (H-alpha) that has been artificially expanded into 3-D. Credit: ALMA (ESO/NAOJ/NRAO); R. Indebetouw

    NASA/ESA Hubble Telescope

    Recently, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to probe the heart of this supernova, named SN 1987A. ALMA’s ability to see remarkably fine details allowed the researchers to produce a detailed 3-D rendering of newly formed molecules inside the supernova remnant. These results are published in the Astrophysical Journal Letters.

    The researchers also discovered a variety of previously undetected molecules in the remnant. Those results will appear in the Monthly Notices of the Royal Astronomical Society.

    “When this supernova exploded now more than 30 years ago, astronomers knew much less about the way these events reshape interstellar space and how the hot, glowing debris from an exploded star eventually cools and produces new molecules,” said Rémy Indebetouw, an astronomer at the University of Virginia and the National Radio Astronomy Observatory (NRAO) in Charlottesville. “Thanks to ALMA we can finally see cold ‘star dust’ as it forms, revealing important insights into the original star itself and the way supernovas create the basic building blocks of planets.”

    Supernovas – Star Death to Dust Birth

    Prior to ongoing investigations of SN 1987A, there was only so much astronomers could determine about these explosive cosmic events.

    It was well understood that massive stars, those approximately 10 times the mass of our sun, ended their lives in spectacular fashion. When these stars run out of fuel, there is no longer enough heat and energy to fight back against the force of gravity. The outer reaches of the star, once held up by the power of fusion, then come crashing down on the core with tremendous force. The rebound of this collapse triggers an explosion that blasts material into space.

    As the endpoint of massive stars, scientists have learned that supernovas have far-reaching effects on galaxies across the universe. To get a better understanding of these effects, Indebetouw helps break down the impact of these star-shattering events. “The reason some galaxies have the appearance that they do today is in large part because of the supernovas that have occurred in them,” he said. “Though less than 10 percent of stars in galaxies , the ones that explode as supernovas dominate the evolution of galaxies.”

    Throughout the observable universe, supernovas are quite common, but since they appear – on average – about once every 50 years in a galaxy the size of the Milky Way, astronomers have precious few opportunities to study one from its first detonation to the point where it cools enough to form new molecules. Though SN 1987A is not technically in our home galaxy, it is still close enough for ALMA and other telescopes to study in fine detail.

    4
    Astronomers combined observations from three different observatories to produce this colorful, multiwavelength image of the intricate remains of Supernova 1987A.The red color shows newly formed dust in the center of the supernova remnant, taken at submillimeter wavelengths by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile. The green and blue hues reveal where the expanding shock wave from the exploded star is colliding with a ring of material around the supernova. The green represents the glow of visible light, captured by NASA’s Hubble Space Telescope. The blue color reveals the hottest gas and is based on data from NASA’s Chandra X-ray Observatory.The ring was initially made to glow by the flash of light from the original explosion. Over subsequent years the ring material has brightened considerably as the explosion’s shock wave slams into it. Supernova 1987A resides 163,000 light-years away in the Large Magellanic Cloud, where a firestorm of star birth is taking place. Credit: NASA/ESA, ALMA (ESO/NAOJ/NRAO)

    NASA/Chandra Telescope

    Capturing 3-D Image of SN1987A with ALMA

    For decades, radio, optical, and even X-ray observatories have studied of SN 1987 A, but obscuring dust in the outer regions of the remnant made it difficult to analyze the supernova’s innermost core. ALMA’s ability to observe at millimeter wavelengths – a region of the electromagnetic spectrum between infrared and radio light – made it possible to see through the intervening dust and gas and study the abundance and location of newly formed molecules – especially silicon monoxide (SiO) and carbon monoxide (CO), which shine brightly at the short submillimeter wavelengths that ALMA can perceive.

    In the new ALMA image and animation, emission from SiO (colored purple) and CO (colored yellow) is located in discrete clumps within the core of SN 1987A. Indebetouw said that scientists previously predicted how and where these molecules would appear, but without ALMA they were unable to capture images with high enough resolution to confirm the structure inside the remnant and test those models.

    Aside from obtaining the first 3-D image of SN 1987A, the ALMA data also reveal compelling details about how the physical conditions have changed and continues to change over time. These observations also provide insights into the physical instabilities in a supernova.

    New Insights from SN 1987A

    Earlier observations with ALMA verified that SN 1987A produced a massive amount of dust. The new observations provide more details on how the supernova made the dust as well as the type of molecules found in it.

    “One of our goals was to observe SN 1987A in a blind search for other molecules,” said Indebetouw. “We expected to find carbon monoxide and silicon monoxide, since we had previously detected these molecules.” The astronomers, however, were excited to find the previously undetected molecules HCO+ and sulfur monoxide (SO).

    “These molecules had never been detected in a young supernova remnant before,” noted Indebetouw. “HCO+ is especially interesting because its formation requires particularly vigorous mixing during the explosion.”

    The current observations allow the astronomers to estimate that about 1 in 1000 silicon atoms from the exploded star are now found in SiO molecules; astronomers think that the majority of the silicon is currently in dust grains. Even the small amount of SiO that is present is 100 times greater than predicted by dust formation models. These new observations will aid astronomers in refining these models.

    These observations also find that 10 percent or more of the carbon in the exploded star is currently in a CO molecule. Only a few out of every million carbon atoms are in a HCO+ molecule.

    New Questions and Future Research

    Even though the new ALMA observations shed important light on SN 1987A, there are still several questions that remain. Exactly how abundant are the molecules of HCO+ and SO? Are there other molecules that have yet to be detected? How will the 3-D structure of SN 1987A continue to change over time?

    Future ALMA observations at different wavelengths may also shed light on what sort of compact object — a pulsar or neutron star — resides at the center of this object. Such an object has been predicted but so far not detected inside SN 1987A.

    There are many animations in the article which are [foolishly] in Vimeo, which I cannot reproduce. See the full article for these animations.

    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 12:57 pm on July 7, 2017 Permalink | Reply
    Tags: ALMA, Dr. Sean Dougherty, new ALMA Director for next 5 years   

    From ALMA: “ALMA Selects New Director” 

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

    07 July 2017

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

    1
    Dr. Sean Dougherty. Credit: Catherine Vlahakis

    After a competitive selection process that began in January 2017, the international governing board of the Atacama Large Millimeter/submillimeter Array (ALMA) has selected Dr. Sean Dougherty as the new ALMA Director for a 5-year term beginning in April 2018.

    Dougherty is currently the director of the Dominion Radio Astrophysical Observatory, Canada’s national radio astronomy facility, run by NRC Herzberg Astronomy and Astrophysics.

    2
    The Dominion Radio Astrophysical Observatory is a research facility founded in 1960 and located south-west of Okanagan Falls, British Columbia, Canada. The site houses three instruments – an interferometric radio telescope, a 26-m single-dish antenna, and a solar flux monitor – and support engineering laboratories. The DRAO is operated by the Herzberg Institute of Astrophysics of the National Research Council of the Canadian government.

    He has served as a member of the ALMA Board representing North America for four years and was the chair of the ALMA Budget Committee for the last two years.

    Dougherty received his bachelor’s degree in mathematics and physics from the University of Nottingham, England, in 1983 and his Ph.D. in astrophysics from the University of Calgary, Canada, in 1993.

    Dougherty has more than 20 years of science and engineering management experience in radio astrophysics. This includes Canada’s contributions to international radio astronomy facilities and R&D projects as well as leadership of major science and engineering activities at the Dominion Radio Astrophysical Observatory. He also led the design and construction of the WIDAR correlator for the Karl G. Jansky Very Large Array and is currently leading the international consortium designing the correlator and beamformer for the Square Kilometer Array.

    WIDAR correlator at VLA

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

    SKA Square Kilometer Array

    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 3:10 pm on June 30, 2017 Permalink | Reply
    Tags: ALMA, ALMA Reveals Turbulent Birth of Twin Baby Stars, , , , ,   

    From ALMA: “ALMA Reveals Turbulent Birth of Twin Baby Stars” 

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

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

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

    Tel: +81 422 34 3630

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

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

    1
    Artist’s impression of the baby twin system IRAS 04191+1523. Credit: ALMA (ESO/NAOJ/NRAO)

    Using the Atacama Large Millimeter/submillimeter Array (ALMA), researchers obtained a critical clue to an underlying problem: how are widely separated twin stars formed? The team found very low mass newborn twin stars with misaligned rotation axes. This misalignment indicates that they were formed in a pair of fragmented gas clouds produced through turbulence, not via evolution of tightly-coupled twin. This finding strongly supports the turbulent fragmentation theory of binary star formation down to the substellar regime.

    An international team of astronomers led by Jeong-Eun Lee in Kyung Hee University, Korea, observed the baby twin star system IRAS 04191+1523 with ALMA. Thanks to the high resolution of ALMA, the team successfully imaged the rotation of the gas disks around the very low mass twin stars and found that the rotation axes of the two stars are misaligned.

    “This revelation is particularly interesting because both baby stars’ masses derived from our ALMA data are about 10% of the solar mass, which is very low. The formation of very low mass wide binary stars has been a mystery. But our result is strong evidence that wide binaries of these very low mass stars and even brown dwarfs can form in the same way as normal stars via turbulent fragmentation.” said Lee.

    More than a half of the stars in the Universe are born as twins or multiple systems. Therefore, unveiling the formation mechanism of twin stars is crucial for a comprehensive understanding of stellar evolution.

    There are two types of multiple stars: close systems and widely separated systems. Astronomers have witnessed a close system being formed via fragmentation of the gas disk around the firstborn stars [1]. On the other hand, there is no clear evidence on how widely separated systems are formed. Some researchers assume that a close system evolves into a wide system over millions of years due to dynamical interactions, but others guess that turbulence in a gas cloud fragments the cloud into smaller ones and stars are formed in each small cloud.

    Aiming to find clues to the formation of wide binary systems, the researchers selected IRAS 04191+1523 as the target of their ALMA observations. The separation of the two stars is about 30 times the distance of Neptune from the Sun and classified as a wide binary. The age of the system is estimated to be far younger than half a million years old, therefore it is a good target to investigate the initial phase of wide binary formation.

    2
    Composite image of the very young baby twin star system IRAS 04191+1523. ALMA revealed the disks around two stars (white) and a common gas envelope (yellow). Red color shows the distribution of a dense cloud seen in far infrared light observed by the Herschel Space Observatory. Credit: ALMA (ESO/NAOJ/NRAO), Lee et al., ESA/Herschel/PACS

    ESA/Herschel spacecraft

    The team analyzed the signal from carbon monoxide molecules in the disks to derive their motion and found that the two disks around the baby stars are not aligned. The angle between the rotation axes of the disks is 77 degrees.

    “The system is too young for the alignment of axes to have been modified by interactions,” said Lee [2], “so we conclude that this system was formed by the turbulent fragmentation of a cloud, not by disk fragmentation and migration.”

    If a binary system is formed via disk fragmentation, the rotational moment of the gas aligns the axes of two stars. This alignment would be maintained even if the separation between the two is extended via tidal interactions. The misalignment of the axes in the infant system IRAS 04191+1523 clearly rejects this scenario.

    Notes

    ALMA revealed the detailed structure of the ongoing fragmentation of a gas disk around a young triple star system L1448 IRS 3B.

    Previous ALMA observations of a young binary system HK Tauri show that the two disks are misaligned. However, HK Tauri is much more evolved than IRAS 04191+1523 and it is difficult to reject the possibility of orbit evolution to become a widely-separated system.

    Additional information

    These observation results were published as Lee et al. Formation of Wide Binaries by Turbulent Fragmentation in Nature Astronomy on June 30, 2017.

    The research team members are:

    Jeong-Eun Lee (Kyung Hee University), Seokho Lee (Kyung Hee University), Michel Dunham (State University of New York at Fredonia), Ken’ichi Tatematsu (National Astronomical Observatory of Japan / SOKENDAI), Minho Choi (Korea Astronomy and Space Science Institute), Edwin A. Bergin (University of Michigan), Neal J. Evans II (Korea Astronomy and Space Science Institute / The University of Texas at Austin)

    This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (grant No. NRF-2015R1A2A2A01004769) and the Korea Astronomy and Space Science Institute under the R&D program (Project No. 2015-1-320-18) supervised by the Ministry of Science, ICT and Future Planning, Korea.

    See the full article here .

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

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

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

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  • richardmitnick 1:55 pm on June 26, 2017 Permalink | Reply
    Tags: ALMA, , , , , , Fomalhaut debris disk   

    From astrobites: “A New Glow in the Eye of Sauron” 

    Astrobites bloc

    Astrobites

    Jun 26, 2017
    Mara Zimmerman

    Title: A Complete ALMA Map of the Fomalhaut Debris Disk
    https://arxiv.org/pdf/1705.05867.pdf
    Authors: Meredith Macgregor, Luca Matrá, Paul Kalas, et al.
    Lead Author’s Institution: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

    Status: Accepted to ApJ [open access]
    _________________________________________________________________________

    The Fomalhaut debris disk is one of the most recognizable circumstellar disks—mainly because images of it bear an uncanny resemblance to a certain tyrant of Middle Earth.

    1
    An image of the debris disk, showing optical detection of dust (Source: Kalas et al. 2005).

    The Fomalhaut system contains a dusty-debris disk, which gives the images their distinctive glowing eye appearance. Because of its proximity and unusual features, this debris disk is quite well studied, but, as the authors of this paper demonstrate, there is still much more we can learn from Fomalhaut. It has been shown to have a companion, Fomalhaut b, on a highly eccentric orbit. The interaction between Fomalhaut b and the debris disk is what makes this system so intriguing; when Fomalhaut b was first discovered, it was thought to be a massive planet, however new observations in today’s paper cast doubt on this hypothesis. Given Fomalhaut b’s lack of brightness in the optical and unusual brightness in the infrared, the authors of this paper suggest that Fomalhaut b is likely a giant dust cloud.

    In this paper, the authors use observations from the ALMA (Atacama Large Millimeter/submillimeter Array) observatory to reveal the structure of the Fomalhaut disk, and observe an unusual glow in the disk corresponding to the apocenter of the system.

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

    4
    Figure 2: These ALMA images of Fomalhaut show the apocenter glow. The difference in brightness between the North-west (apocenter) and South-east (pericenter) sides reflects the surface density distribution of the disk. The image on the left is just the ALMA image while the image on the right is corrected by the HST images. On the right, the apocenter glow is clearly visible.

    See the full article here .

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    What do we do?

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

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

     
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