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  • richardmitnick 10:42 am on August 23, 2022 Permalink | Reply
    Tags: "Case Solved:: Missing Carbon Monoxide was Hiding in the Ice", A huge chunk of carbon monoxide is missing in all observations of disks if astronomers' current predictions of its abundance are correct., A new model has been validated by observations with ALMA., , Astrochemistry, , , Carbon monoxide in planetary nurseries: the compound is ultra-bright and extremely common in protoplanetary disks., Carbon monoxide inaccuracies could have huge implications for the field of astrochemistry., Carbon monoxide is essentially used to trace everything known about disks., Carbon monoxide is three to 100 times less than it should be; it's off by a really huge amount., , , , In planetary disks carbon monoxide is lurking in large chunks of ice solving the decade-old question 'Where is the CO?', Scientists compared CO output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya; HD 163296; DM Tau and IM Lup., Something hasn't been adding up when it comes to carbon monoxide observations., The four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice which is currently undetectable with a telescope.,   

    From The Harvard-Smithsonian Center for Astrophysics: “Case Solved:: Missing Carbon Monoxide was Hiding in the Ice” 

    From The Harvard-Smithsonian Center for Astrophysics

    8.22.22
    Nadia Whitehead
    Public Affairs Officer
    Center for Astrophysics | Harvard & Smithsonian
    nadia.whitehead@cfa.harvard.edu
    617-721-7371

    In planetary disks carbon monoxide is lurking in large chunks of ice solving the decade-old question ‘Where is the CO?’

    1
    Credit: M.Weiss/Center for Astrophysics | CfA

    Astronomers frequently observe carbon monoxide in planetary nurseries: the compound is ultra-bright and extremely common in protoplanetary disks — regions of dust and gas where planets form around young stars — making it a prime target for scientists.

    But for the last decade or so, something hasn’t been adding up when it comes to carbon monoxide observations, says Diana Powell, a NASA Hubble Fellow at the Center for Astrophysics | Harvard & Smithsonian.

    A huge chunk of carbon monoxide is missing in all observations of disks if astronomers’ current predictions of its abundance are correct.

    Now, a new model — validated by observations with ALMA — has solved the mystery: carbon monoxide has been hiding in ice formations within the disks. The findings are described today in the journal Nature Astronomy [below].

    “This may be one of the biggest unsolved problems in planet-forming disks,” says Powell, who led the study. “Depending on the system observed, carbon monoxide is three to 100 times less than it should be; it’s off by a really huge amount.”

    And carbon monoxide inaccuracies could have huge implications for the field of astrochemistry.

    “Carbon monoxide is essentially used to trace everything we know about disks — like mass, composition and temperature,” Powell explains. “This could mean many of our results for disks have been biased and uncertain because we don’t understand the compound well enough.”

    Intrigued by the mystery, Powell put on her detective hat and leaned on her expertise in the physics behind phase changes — when matter morphs from one state to another, like a gas changing into a solid.

    On a hunch, Powell made alterations to an astrophysical model that’s currently used to study clouds on exoplanets, or planets beyond our solar system.

    “What’s really special about this model is that it has detailed physics for how ice forms on particles,” she explains. “So how ice nucleates onto small particles and then how it condenses. The model carefully tracks where ice is, on what particle it’s located on, how big the particles are, how small they are and then how they move around.”

    Powell applied the adapted model to planetary disks, hoping to generate an in-depth understanding of how carbon monoxide evolves over time in planetary nurseries. To test the model’s validity, Powell then compared its output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya; HD 163296; DM Tau and IM Lup.

    The results and models worked really well, Powell says.

    The new model lined up with each of the observations, showing that the four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice which is currently undetectable with a telescope.

    Radio observatories like ALMA allow astronomers to view carbon monoxide in space in its gas phase, but ice is much harder to detect with current technology, especially large formations of ice, Powell says.

    The model shows that unlike previous thinking, carbon monoxide is forming on large particles of ice — especially after one million years. Prior to a million years, gaseous carbon monoxide is abundant and detectable in disks.

    “This changes how we thought ice and gas were distributed in disks,” Powell says. “It also shows that detailed modelling like this is important to understand the fundamentals of these environments.”

    Powell hopes her model can be further validated using observations with NASA’s Webb Telescope — which may be powerful enough to finally detect ice in disks, but that remains to be seen.

    Powell, who loves phase changes and the complicated processes behind them, says she is in awe of their influence. “Small-scale ice formation physics influences disk formation and evolution — now that’s really cool.”

    Science paper:
    Nature Astronomy

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The The Harvard-Smithsonian Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

    Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory, one of NASA’s Great Observatories.

    GMT Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s NSF NOIRLab NOAO Las Campanas Observatory(CL) some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

    National Aeronautics and Space Administration Chandra X-ray telescope.

    Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System, for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

    The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University and the Smithsonian Institution. This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

    History of the Smithsonian Astrophysical Observatory (SAO)

    Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

    In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

    With the creation of National Aeronautics and Space Administration the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

    History of Harvard College Observatory (HCO)

    Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

    Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

    Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

    Joint history as the Center for Astrophysics (CfA)

    The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

    This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with University of California- Berkeley, was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

    Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world.

    Harvard Smithsonian Center for Astrophysics Fred Lawrence Whipple Observatory located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU)/National Aeronautics and Space Administration SOHO satellite. Launched in 1995.

    National Aeronautics Space Agency NASA Kepler Space Telescope

    CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

    The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

    The CfA Today

    Research at the CfA

    Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

    The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

    CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawaii, Altitude 4,205 m (13,796 ft).

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including The University of Chicago ; The University of California-Berkeley ; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; The University of Colorado- Boulder; McGill (CA) University, The University of Illinois, Urbana-Champaign; The University of California- Davis; Ludwig Maximilians Universität München(DE); DOE’s Argonne National Laboratory; and The National Institute for Standards and Technology.

    Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker. The Johns Hopkins University Applied Physics Lab.

    National Aeronautics and Space Administration Solar Dynamics Observatory.

    Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構] (JP)/National Aeronautics and Space Administration HINODE spacecraft.

    SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

    Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation.

    The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

    In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

     
  • richardmitnick 11:08 pm on February 22, 2022 Permalink | Reply
    Tags: "What ingredients went into the galactic blender to create the Milky Way?", , Astrochemistry, , , ,   

    From ARC Centres of Excellence for All Sky Astrophysics in 3D(AU): “What ingredients went into the galactic blender to create the Milky Way?” 

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence for All Sky Astrophysics in 3D(AU)

    2.22.22

    Tamzin Byrne,
    tamzin@scienceinpublic.com.au
    +61 432 47 42 48

    Niall Byrne,
    niall@scienceinpublic.com.au
    +61 417 131 977

    Authors:

    Sven Buder, Karin Lind, Melissa K Ness, Diane K Feuillet, Danny Horta, Stephanie Monty, Tobias Buck, Thomas Nordlander, Joss Bland-Hawthorn, Andrew R Casey, Gayandhi M De Silva, Valentina D’Orazi, Ken C Freeman, Michael R Hayden, Janez Kos, Sarah L Martell, Geraint F Lewis, Jane Lin, Katharine J Schlesinger, Sanjib Sharma, Jeffrey D Simpson, Dennis Stello, Daniel B Zucker, Tomaž Zwitter, Ioana Ciucă, Jonathan Horner, Chiaki Kobayashi, Yuan-Sen Ting (丁源森), Rosemary F G Wyse.

    Our galaxy is a giant ‘smoothie’ of blended stars and gas but a new study tells us where the components came from.

    In its early days, the Milky Way was like a giant smoothie, as if galaxies consisting of billions of stars, and an enormous amount of gas had been thrown together into a gigantic blender.

    But a new study picks apart this mixture by analysing individual stars to identify which originated inside the galaxy and which began life outside.

    “Although the Milky Way is our home galaxy, we still do not understand how it formed and evolved,” says researcher Sven Buder from the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and the Australian National University.

    His paper, published this week in the MNRAS analyses the light from stars in detail, helping to understand what elements went into the creation of the Milky Way we know today.

    “The Milky Way ate up lots of smaller galaxies but, until recently, we did not have enough evidence of that to say for sure,” Buder says.

    “That’s because simple images of stars in our Milky Way look the same – whether they were born inside the galaxy or outside and then blended into the galaxy.”

    Buder and colleagues in the Galactic Archaeology with HERMES (GALAH) team used Australia’s largest optical telescope, the Anglo-Australian Telescope (AAT), at Siding Spring Observatory to split light from more than 600,000 stars into wavelengths with the HERMES (High Efficiency and Resolution Multi-Element Spectrograph) instrument.

    This effectively creates 600,000 stellar rainbows known as spectra.

    Within each of these rainbows are specific bands of light – rather like tiny unique barcodes – that vary depending on a star’s chemical composition.

    1
    Just by looking at how abundant are sodium, iron, magnesium, and manganese in a star, we can tell apart stars born in the Milky Way (green) or outside (yellow).

    “If an image is worth a thousand words, these spectra are worth more than a thousand pictures,” says Buder. “By ‘scanning’ these stellar barcodes, we measured how abundant 30 elements, such as sodium, iron, magnesium, and manganese, were, and how they appeared in different concentrations depending on where the star was born.”

    This discovery is an early step towards reconstructing a picture of the “childhood” of the Milky Way to get an idea of the size of the galaxies that it consumed in the process.

    “It could also help us understand how several of the features of the galaxy we know today came into being,” says Buder.

    One mystery the new observations could help solved is why there are two distinct groups of stars in the disc that we see as the “milky” band in the night sky.

    3
    The Milky Way has two distinct populations of stars, one older than the other. The older stars have moved so they look like they bulge out of the main plane of the Milky Way, while the younger stars form a much thinner band in the plane.

    “The Milky Way spread out across the night sky is a familiar sight, and when we look at it, we are actually gazing into the centre of our galaxy with its billions of stars,” says Buder.

    “But we are looking at two populations of stars, one much older than the other. The old stars have moved so they look like they bulge out of the main plane of the Milky Way, while the younger stars form a much thinner band in the plane.

    “But we don’t know why this has happened and our latest findings of the remnants of gigantic, galactic collisions may help us understand,” says Buder.

    Buder’s paper provides the latest revelations relying on data from the Gaia project – an ambitious satellite mission to chart a three-dimensional map of the Milky Way to help understand its orbits, composition, formation, and evolution.

    The Gaia satellite measurements can help us to find candidates of previously extragalactic stars, because they still move differently from a typical Milky Way star.

    But the extragalactic origin of a star can only be confirmed by its chemical fingerprint.

    The GALAH survey is an Australian-led Large Observing Program using the HERMES instrument to obtain the highest spectral resolution multi-dimensional datasets for more than a million stars of all ages and locations in the Milky Way, to trace the full history of the Galaxy.

    The HERMES instrument was built by the Australian Astronomical Observatory, which has since become the Astralis Instrumentation Consortium.

    3
    HERMES instrument.

    Astralis receives $5M per year from the NCRIS programme, and combines expertise from Macquarie University, the University of Sydney, and ANU. Astralis will strengthen Australia’s competitiveness for instrumentation contracts at major observatories world-wide.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (AU)

    Unifies over 200 world-leading astronomers to understand the evolution of the matter, light, and elements from the Big Bang to the present day.

    We are combining Australian innovative 3D optical and radio technology with new theoretical supercomputer simulations on a massive scale, requiring new big data techniques.

    Through our nationwide training and education programs, we are training young scientific leaders and inspiring high-school students into STEM sciences to prepare Australia for the next generation of telescopes: the Square Kilometre Array and the Extremely Large Optical telescopes.

    The objectives for the ARC Centres of Excellence (AU) are to to:

    Undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge.

    Link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems.

    Develop relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research

    Build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students.

    Provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers.

    Offer Australian researchers opportunities to work on large-scale problems over long periods of time.

    Establish Centres that have an impact on the wider community through interaction with SKA Murchison Widefield Array (AU), Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO), on the traditional lands of the Wajarri peoples.

    The Murchison Radio-astronomy Observatory,on the traditional lands of the Wajarri peoples, in outback Western Australia will house up to 130,000 antennas like these and the associated advanced technologies.

    EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

    SKA ASKAP Pathfinder Radio Telescope

     
  • richardmitnick 10:45 pm on May 11, 2021 Permalink | Reply
    Tags: "First discovery of methanol in a warm planet-forming disk", , Astrochemistry, , , , , , ,   

    From Netherlands Research School for Astronomy [Nederlandse Onderzoekschool Voor Astronomie] (NL) via phys.org : “First discovery of methanol in a warm planet-forming disk” 

    From Netherlands Research School for Astronomy [Nederlandse Onderzoekschool Voor Astronomie] (NL)

    via

    phys.org

    1
    A map of the methanol (white) in the planetary disk around the star HD 100546. The red line is the orbit that the ‘cold’ planet Neptune would have if it were orbiting this star. So the white methanol is almost entirely in the ‘warm’ part of the planet forming disk. Credit: ALMA/Booth et al.

    An international team of researchers led by Alice Booth (Leiden University [Universiteit Leiden] (NL)) have discovered methanol-ijs in the warm part of a planet-forming disk. The methanol cannot have been produced there and must have originated in the cold gas clouds from which the star and the disk formed. Thus, the methanol is inherited. If that is common, it could give the development of life a flying start. The researchers will publish their findings on Monday evening in Nature Astronomy.

    Methanol, CH3OH, is one of the simplest complex molecules. It is considered by astronomers to be a precursor for the pre-biotic chemistry essential for life because it can be used to form, for example, amino acids and proteins. Researchers had already shown that methanol is present in one cold planet-forming disk around a nearby star, in comets and in the cold gas clouds from which stars form. Now, for the first time, a large reservoir of methanol has been discovered in a warm planet-forming disk.

    This reservoir of methanol cannot have formed in the warm disk itself, as this is chemically impossible. The researchers therefore propose that the methanol ice was already present on the dust grains in the cold gas cloud from which the star and the disk originated.

    Research leader Alice Booth (Leiden University): “This is a very exciting and surprising result. Whilst warm methanol has been detected in the warm, young disks, because of the nature of this disk this is the first clear observational evidence that complex organic molecules can be ‘inherited’ from the earlier cold dark clouds phase.”

    2
    The star HD 100546 has a large protoplanetary disk. In 2013, a possible planet-in-the-making was found in the cold outer region of this disk (orange dot). Today’s study is about the warmer inner part of the disk. The black spots in the image are artefacts. Credit: ESO/NASA/ESA/Ardila et al.

    The researchers made their observations on the planet-forming disk around the much-studied star HD 100546. This disk and star are about 10 million years old and are located about 360 light years from Earth in the direction of the southern constellation of the Fly (Musca).

    The researchers used the ALMA observatory, located high up in the Chilean Andes. The astronomers were actually looking for the simple molecule sulfur monoxide, but to their surprise they also detected methanol lines in their spectra.

    In the future, the researchers hope to collect more data so that they can observe the methanol lines at higher spatial resolution. They will also search for more complex oxygen-containing molecules such as dimethyl ether (C2H6O), methyl formate (C2H4O2) and acetaldehyde (C2H4O). These molecules, which are also found in comets and dark clouds, are believed to some of the key ingredients for prebiotic chemistry.

    3
    Composed image of the star HD100546 (right) with the methanol reservoir (left) in its warm part of the protoplanetary disk. Credit: ALMA/Booth et al. & ESO/NASA/ESA/Ardila et al.

    The researchers want to compare the quantities of these substances in the planet-forming disk with the quantities in comets. This way, they can get a better idea of what proportion of the organic content survives the star formation process. And that, in turn, is important for a better understanding of the chemical processes during the formation of planets. After all, icy asteroids such as comets are the building blocks of planets.

    See the full article here.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NOVA stands for ‘Nederlandse Onderzoekschool Voor Astronomie’, i.e., the ‘Netherlands Research School for Astronomy’. It is the alliance of the astronomical institutes of the University of Amsterdam [Universiteit van Amsterdam](NL), University of Gronigen [Rijksuniversiteit Groningen] (NL), Leiden University [Universiteit Leiden](NL), and Radboud University [Radboud Universiteit](NL). Astronomy is considered to be top-science in The Netherlands. NOVA was selected as top-research school in 1998 following an open national competition, and is as such receiving substantial funding by the Dutch Ministry of Education.

    NOVA’s mission is to carry out frontline astronomical research in the Netherlands, to train young ast ronomers at the highest international levels, and to share our new discoveries with society.

    NOVA: collaboration

    The astronomical institutes at the universities of Amsterdam, Groningen, Leiden and Nijmegen together form NOVA. NOVA closely collaborates with the two other research institutes that are active in the field of astronomy in the Netherlands: The space research institute SRON Netherlands Institute for Space Research (NL) and the ASTRON Institute for Radio Astronomy(NL).

    Collaboration and coordination of all partners in Dutch astronomy takes place within the Astronomy Council (RvdA) and the creation of decadal strategic plans and midterm updates by the RvdA.

    NOVA astronomers rely heavily on the world-class facilities of the European Southern Observatory (ESO) (EU), most notably the VLT telescopes and the ALMA array.

    A large fraction of the instrument projects that NOVA participates in are targeted at these facilities, as well as the future Extremely Large Telescope.

     
  • richardmitnick 7:16 pm on April 8, 2021 Permalink | Reply
    Tags: "Scientists shed more light on molecules linked to life on other planets", Astrochemistry, , , Exopanet Research, ,   

    From University of New South Wales (AU) : “Scientists shed more light on molecules linked to life on other planets” 

    U NSW bloc

    From University of New South Wales (AU)

    09 Apr 2021
    Lachlan Gilbert

    1
    Phosphine detected in the atmosphere of Venus has scientists divided about whether or not it signifies primitive life on the planet. Credit: Shutterstock.

    The search for life on other planets has received a major boost after scientists revealed the spectral signatures of almost 1000 atmospheric molecules that may be involved in the production or consumption of phosphine, a study led by UNSW Sydney revealed.

    Scientists have long conjectured that phosphine – a chemical compound made of one phosphorous atom surrounded by three hydrogen atoms (PH3) – may indicate evidence of life if found in the atmospheres of small rocky planets like our own, where it is produced by the biological activity of bacteria.

    So when an international team of scientists last year claimed to have detected phosphine in the atmosphere of Venus, it raised the tantalising prospect of the first evidence of life on another planet – albeit the primitive, single-celled variety.

    But not everyone was convinced, with some scientists questioning whether the phosphine in Venus’s atmosphere was really produced by biological activity, or whether phosphine was detected at all.

    Now an international team, led by UNSW Sydney scientists, has made a key contribution to this and any future searches for life on other planets by demonstrating how an initial detection of a potential biosignature must be followed by searches for related molecules.

    In a paper published today in the journal Frontiers in Astronomy and Space Sciences, they described how the team used computer algorithms to produce a database of approximate infrared spectral barcodes for 958 molecular species containing phosphorous.

    2
    A diagram summarising the achievements of the research team. Image: UNSW.

    As UNSW School of Chemistry’s Dr Laura McKemmish explains, when scientists look for evidence of life on other planets, they don’t need to go into space, they can simply point a telescope at the planet in question.

    “To identify life on a planet, we need spectral data,” she says.

    “With the right spectral data, light from a planet can tell you what molecules are in the planet’s atmosphere.”

    Phosphorus is an essential element for life, yet up until now, she says, astronomers could only look for one polyatomic phosphorus-containing molecule, phosphine.

    “Phosphine is a very promising biosignature because it is only produced in tiny concentrations by natural processes. However, if we can’t trace how it is produced or consumed, we can’t answer the question of whether it is unusual chemistry or little green men who are producing phosphine on a planet,” says Dr McKemmish.

    To provide insight, Dr McKemmish brought together a large interdisciplinary team to understand how phosphorus behaves chemically, biologically and geologically and ask how this can be investigated remotely through atmospheric molecules alone.

    “What was great about this study is that it brought together scientists from disparate fields – chemistry, biology, geology – to address these fundamental questions around the search for life elsewhere that one field alone could not answer,” says astrobiologist and co-author on the study, Associate Professor Brendan Burns.

    Dr McKemmish continues: “At the start, we looked for which phosphorous-bearing molecules – what we called P-molecules – are most important in atmospheres but it turns out very little is known. So we decided to look at a large number of P-molecules that could be found in the gas-phase which would otherwise go undetected by telescopes sensitive to infrared light.”

    Barcode data for new molecular species are normally produced for one molecule at a time, Dr McKemmish says, a process that often takes years. But the team involved in this research used what she calls “high-throughput computational quantum chemistry” to predict the spectra of 958 molecules within only a couple of weeks.

    “Though this new dataset doesn’t yet have the accuracy to enable new detections, it can help prevent misassignments by highlighting the potential for multiple molecular species having similar spectral barcodes – for example, at low resolution with some telescopes, water and alcohol could be indistinguishable.

    “The data can also be used to rank how easy a molecule is to detect. For example, counter-intuitively, alien astronomers looking at Earth would find it much easier to detect 0.04% CO2 in our atmosphere than the 20% O2. This is because CO2 absorbs light much more strongly than O2 – this is actually what causes the greenhouse effect on Earth.”

    Life on exoplanets

    Regardless of the outcomes from the debate about the existence of phosphine in Venus’s atmosphere and the potential signs of life on the planet, this recent addition to the knowledge of what can be detected using telescopes will be important in the detection of potential signs of life on exoplanets – planets in other solar systems.

    “The only way we’re going to be able to look at exoplanets and see whether there’s life there is to use spectral data collected by telescopes – that is our one and only tool,” says Dr McKemmish.

    “Our paper provides a novel scientific approach to following up the detection of potential biosignatures and has relevance to the study of astrochemistry within and outside the Solar System,” says Dr McKemmish. “Further studies will rapidly improve the accuracy of the data and expand the range of molecules considered, paving the way for its use in future detections and identifications of molecules.”

    Fellow co-author and CSIRO astronomer Dr Chenoa Tremblay says the team’s contribution will be beneficial as more powerful telescopes come online in the near future.

    “This information has come at a critical time in astronomy,” she says.

    “A new infrared telescope called the James Web Space Telescope is due to launch later this year and it will be far more sensitive and cover more wavelengths than its predecessors like the Herschel Space Observatory.


    We will need this information at a very rapid rate to identify new molecules in the data.”

    She says although the team’s work was focused on the vibrational motions of molecules detected with telescopes sensitive to infrared light, they are currently working to extend the technique to the radio wavelengths as well.

    “This will be important for current and new telescopes like the upcoming Square Kilometre Array to be built in Western Australia.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    UNSW Campus

    Welcome to University of New South Wales (AU), one of Australia’s leading research and teaching universities. At UNSW, we take pride in the broad range and high quality of our teaching programs. Our teaching gains strength and currency from our research activities, strong industry links and our international nature; UNSW has a strong regional and global engagement.

    In developing new ideas and promoting lasting knowledge we are creating an academic environment where outstanding students and scholars from around the world can be inspired to excel in their programs of study and research. Partnerships with both local and global communities allow UNSW to share knowledge, debate and research outcomes. UNSW’s public events include concert performances, open days and public forums on issues such as the environment, healthcare and global politics. We encourage you to explore the UNSW website so you can find out more about what we do.

    Established in 1949, UNSW is a research university, ranked 44th in the world in the 2021 QS World University Rankings and 67th in the world in the 2021 Times Higher Education World University Rankings. UNSW is one of the founding members of the Group of Eight, a coalition of Australian research-intensive universities, and of Universitas 21, a global network of research universities. It has international exchange and research partnerships with over 200 universities around the world.

    The university comprises seven faculties, through which it offers bachelor’s, master’s and doctoral degrees. The main campus is in the Sydney suburb of Kensington, 7 kilometres (4.3 mi) from the Sydney CBD. The creative arts faculty, UNSW Art & Design, is located in Paddington, and subcampuses are located in the Sydney CBD as well as several other suburbs, including Randwick and Coogee. Research stations are located throughout the state of New South Wales.

    The university’s second largest campus, known as UNSW Canberra(AU) at ADFA, is situated in Canberra, in the Australian Capital Territory (ACT). ADFA is the military academy of the Australian Defence Force, and UNSW Camberra is the only national academic institution with a defence focus.

    Foundation

    The origins of the university can be traced to the Sydney Mechanics’ School of Arts established in 1833 and the Sydney Technical College established in 1878. These institutions were established to meet the growing demand for capabilities in new technologies as the New South Wales economy shifted from its pastoral base to industries fueled by the industrial age.

    The idea of founding the university originated from the crisis demands of World War II, during which the nation’s attention was drawn to the critical role that science and technology played in transforming an agricultural society into a modern and industrial one. The post-war Labor government of New South Wales recognised the increasing need to have a university specialized in training high-quality engineers and technology-related professionals in numbers beyond that of the capacity and characteristics of the existing University of Sydney. This led to the proposal to establish the Institute of Technology, submitted by the then-New South Wales Minister for Education Bob Heffron, accepted on 9 July 1946.

    The university, originally named the “New South Wales University of Technology”, gained its statutory status through the enactment of the New South Wales University of Technology Act 1949 (NSW) by the Parliament of New South Wales in Sydney in 1949.

    Early years

    In March 1948, classes commenced with a first intake of 46 students pursuing programs including civil engineering, mechanical engineering, mining engineering, and electrical engineering. At that time, the thesis programs were innovative. Each course embodied a specified and substantial period of practical training in the relevant industry. It was also unprecedented for tertiary institutions at that time to include compulsory instruction in humanities.

    Initially, the university operated from the inner Sydney Technical College city campus in Ultimo as a separate institution from the college. However, in 1951, the Parliament of New South Wales passed the New South Wales University of Technology (Construction) Act 1951 (NSW) to provide funding and allow buildings to be erected at the Kensington site where the university is now located.

    The lower campus area of the Kensington campus was vested in the university in two lots, in December 1952 and June 1954. The upper campus area was vested in the university in November 1959.

    Expansion

    In 1958, the university’s name was changed to the “University of New South Wales” reflecting a transformation from a technology-based institution to a generalist university. In 1960, the faculties of arts and medicine were established, with the faculty of law coming into being in 1971.

    The university’s first director was Arthur Denning (1949–1952), who made important contributions to founding the university. In 1953, he was replaced by Philip Baxter, who continued as vice-chancellor when this position’s title was changed in 1955. Baxter’s dynamic, if authoritarian, management was central to the university’s first 20 years. His visionary, but at times controversial, energies saw the university grow from a handful to 15,000 students by 1968. The new vice-chancellor, Rupert Myers (1969–1981), brought consolidation and an urbane management style to a period of expanding student numbers, demand for change in university style, and challenges of student unrest.

    In 1962 the academic book publishing company University of New South Wales Press was launched. Now an ACNC not-for-profit entity, it has three divisions: NewSouth Publishing (the publishing arm of the company), NewSouth Books (the sales, marketing and distribution part of the company), and the UNSW Bookshop, situated at the Kensington campus.

    The stabilizing techniques of the 1980s managed by the vice-chancellor, Michael Birt (1981–1992), provided a firm base for the energetic corporatism and campus enhancements pursued by the subsequent vice-chancellor, John Niland (1992–2002). The 1990s had the addition of fine arts to the university. The university established colleges in Newcastle (1951) and Wollongong (1961), which eventually became the University of Newcastle and the University of Wollongong in 1965 and 1975, respectively.

    The former St George Institute of Education (part of the short-lived Sydney College of Advanced Education) amalgamated with the university from 1 January 1990, resulting in the formation of a School of Teacher Education at the former SGIE campus at Oatley. A School of Sports and Leisure Studies and a School of Arts and Music Education were also subsequently based at St George. The campus was closed in 1999.

    Recent history

    In 2010 the Lowy Cancer Research Centre, Australia’s first facility to bring together researchers in childhood and adult cancer, costing $127 million, opened.

    In 2003, the university was invited by Singapore’s Economic Development Board to consider opening a campus there. Following a 2004 decision to proceed, the first phase of a planned $200 m campus opened in 2007. Students and staff were sent home and the campus closed after one semester following substantial financial losses.

    In 2008, it collaborated with two other universities in forming The Centre for Social Impact. In 2019, the university moved to a trimester timetable as part of UNSW’s 2025 Strategy. Under the trimester timetable, the study load changed from offering four subjects per 13-week semester, to three subjects per 10-week term. The change to trimesters has been widely criticised by staff and students as a money-making move, with little consideration as to the well-being of students.

    In 2012 UNSW Press celebrated its 50th anniversary and launched the UNSW Bragg Prize for Science Writing. The annual Best Australian Science Writing anthology contains the winning and shortlisted entries among a collection of the year’s best writing from Australian authors, journalists and scientists and is published annually in the NewSouth imprint under a different editorship. The UNSW Press Bragg Student Prize celebrates excellence in science writing by Australian high school students and is supported by the Copyright Agency Cultural Fund and UNSW Science.

    In the 2019 Student Experience Survey, the University of New South Wales recorded the lowest student satisfaction rating out of all Australian universities, with an overall satisfaction rating of 62.9, which was lower than the overall national average of 78.4. UNSW’s low student satisfaction numbers for 2019 was attributed to the university’s switch to a trimester system.

    On 15 July 2020, the university announced 493 job cuts and a 25 percent reduction in management due to the effects of COVID-19 and a $370 million budget shortfall.

    Research centres

    The university has a number of purpose-built research facilities, including:

    UNSW Lowy Cancer Research Centre is Australia’s first facility bringing together researchers in childhood and adult cancers, as well as one of the country’s largest cancer-research facilities, housing up to 400 researchers.
    The Mark Wainwright Analytical Centre is a centre for the faculties of science, medicine, and engineering. It is used to study the structure and composition of biological, chemical, and physical materials.
    UNSW Canberra Cyber is a cyber-security research and teaching centre.
    The Sino-Australian Research Centre for Coastal Management (SARCCM) has a multidisciplinary focus, and works collaboratively with the Ocean University of China [中國海洋大學; pinyin: Zhōngguó; Hǎiyáng Dàxué](CN) in coastal management research.

     
  • richardmitnick 12:32 pm on January 18, 2021 Permalink | Reply
    Tags: "Interstellar chemistry- low-temperature gas-phase formation of indene in the interstellar medium", , , Astrochemistry, , , , PAHs should neither exist in the interstellar medium nor in meteorites and therefore their ubiquity presents a paradox in astrophysics., , The work offers a new concept on the low-temperature chemistry of carbon found in the galaxy.   

    From phys.org: “Interstellar chemistry- low-temperature gas-phase formation of indene in the interstellar medium” 


    From phys.org

    January 18, 2021
    Thamarasee Jeewandara

    1
    Simplest representatives of two-ring PAHs carrying two six-membered (naphthalene, C10H8; 1) and one six- along with one five-membered ring (indene, C9H8; 2). Whereas the hydrogen abstraction–vinylacetylene addition (HAVA) mechanism can lead to the formation of naphthalene at 10 K, a low-temperature pathway to indene—a fundamental molecular building block of bent PAHs like corannulene (C20H10; 3) and buckminsterfullerene (C60; 4)—is still elusive. Carbon and hydrogen atoms are color-coded in gray and white, respectively, with the carbon backbone of indene highlighted in black. Credit: Science Advances, doi: 10.1126/sciadv.abd4044.

    The interstellar medium and combustion systems contain polycyclic aromatic hydrocarbons (PAHs) as fundamental molecular building blocks that form fullerenes and carbonaceous nanostructures. However, researchers have yet to investigate and understand aromatic molecules carrying five-membered rings that form the essential building blocks of nonplanar polycyclic aromatic hydrocarbons (PAHs), which eventually lead to the formation of interstellar grains or carbonaceous cosmic dust. In a new report now published in Science Advances, Srinivas Doddipatla and a team of scientists in chemistry, physics and astronomy in the U.S. and Russia explored the concept with crossed molecular beam experiments, electronic structure calculations and astrochemical modeling. The work revealed an unusual pathway to form indene (C9H8)—a prototype aromatic molecule with a five membered ring. The mechanism was based on a barrierless biomolecular reaction that involved the simplest organic radical – methylidyne (CH) and styrene (C6H5C2H3) via a hitherto elusive methylidyne addition-cyclization-aromatization (MACA) mechanism. The work offers a new concept on the low-temperature chemistry of carbon found in the galaxy.

    Interstellar chemistry

    In this work, Doddipatla et al. revealed the synthesis of indene molecules based on elementary reactions between the simplest organic radical methylidyne with styrene molecules under single collision conditions. According to a hypothesis proposed by Léger and Puget in 1984, polycyclic aromatic hydrocarbons (PAHs) were assumed to be made of fused benzene rings—to form the missing link between small carbon molecules and carbonaceous nanoparticles or interstellar grains. The PAHs alongside their hydrogenated, alkylated, protonated and ionized counterparts are typically associated with diffuse interstellar bands (DIBs) from the visible to the near infrared and the unidentified infrared (UIR) emission range.

    The compounds encompass about 20 percent of the carbon budget within the galaxy including carbonaceous chondrites (meteorites) such as Murchison, Allende, and Orgueil to advocate for a circumstellar origin of aromatics in carbon-rich asymptotic giant branch stars (AGB). The PAHs also constituted descendent planetary nebulae of AGB stars based on hydrogen abstraction—carbon addition (HACA) sequences. Once formed, however, interstellar PAHs are swiftly destroyed by galactic cosmic rays, photolysis and shock waves with lifetimes of only 108 years. As a result, PAHs should neither exist in the interstellar medium nor in meteorites and therefore their ubiquity presents a paradox in astrophysics. This inconsistency can be solved by assuming the existence of a hitherto elusive low-temperature route for the rapid growth of PAHs in the interstellar medium to overcome their destruction. The identification of such low-temperature pathways will help untangle the origin of PAHs containing five-membered rings such as indene at the most fundamental, microscopic level.

    2
    Laboratory angular distribution and the associated time-of-flight spectra. Laboratory angular distribution at mass-to-charge ratio of 116 (C9H8+) recorded in the reaction of the methylidyne radical (CH; X2Π) with styrene (C8H8; X1A′) (A) and the TOF spectra collected at distinct laboratory angles overlaid with the best fits (B). The solid circles with their error bars indicate the normalized experimental distribution with ±1σ uncertainty, and the open circles indicate the experimental data points of the TOF spectra. The red lines represent the best fits obtained from the optimized center-of-mass (CM) functions. Credit: Science Advances, doi: 10.1126/sciadv.abd4044.

    The experiments

    The team combined crossed molecular beam reactive scattering experiments with electronic structure calculations and astrochemical studies to understand the unexpected gas-phase chemistry initiated by a single collision event. Such phenomena functioned at temperatures as low as 10 K present in molecular clouds such as the Taurus molecular cloud (TMC-1) and the Orion molecular cloud. The hitherto unknown methylidyne addition-cyclization-aromatization (MACA) mechanism explored in this work represented a barrierless path to form indene within the molecular clouds via rapid gas-phase chemistry. The findings disputed established paradigms by suggesting that low temperature initiated the formation of indene, the very first aromatic molecules in the interstellar medium. The carbon backbone of indene also represented a fundamental molecular building block of nonplanar PAHs and may lead to interstellar fullerene (C60, C70) formation.

    3
    Center-of-mass (CM) distributions and the associated flux contour map. CM translational energy flux distribution (A), CM angular flux distribution (B), and the top view of the corresponding flux contour map (C) leading to the formation of indene plus atomic hydrogen in the reaction of methylidyne radical with styrene. Shaded areas indicate the error limits of the best fits accounting for the uncertainties of the laboratory angular distribution and TOF spectra, with the red solid lines defining the best-fit functions. The flux contour map represents the flux intensity of the reactive scattering products as a function of the CM scattering angle (θ) and product velocity (u). The color bar indicates the flux gradient from high (H) intensity to low (L) intensity. Atoms are color-coded in gray (carbon) and white (hydrogen). Credit: Science Advances, doi: 10.1126/sciadv.abd4044.

    Mechanisms of indene formation

    Since elementary reactions of the methylidyne radical and styrene in the gas phase formed the indene molecule, the team combined these findings with simulations and statistics to propose the underlying reaction mechanism. The computations revealed how the methylidyne radical could be added barrierlessly either to the π electron density of the carbon-carbon double bond of the vinyl moiety (C2H3) or to the aromatic ring. During methylidyne addition to the vinyl moiety, they observed a series of thermodynamically stable reactions, followed by cyclization reactions to emit atomic hydrogen accompanied by indene, in an overall exoergic reaction. The alternative methylidyne addition reaction to the benzene moiety was comparatively more complex. After identifying six feasible reaction pathways to form the expected products, the team explored the Rice-Ramsperger-Kassel-Marcus (RRKM) chemical kinetics theory to predict the dominant reaction pathway to form indene. They showed how indene could not be formed by itself in the absence of hydrogen atoms originating from the methylidyne reactant.

    4
    Potential energy surface. The potential energy surface for the reaction of the methylidyne radical with styrene including reaction pathways energetically accessible in the crossed molecular beam experiments via addition to the vinyl (path A) and benzene moiety (paths B and C). The route in red highlights the reaction pathway leading to the formation of indene plus atomic hydrogen. Relative energies are given in units of kJ mol−1. Atoms are color-coded in gray (carbon) and white (hydrogen). Credit: Science Advances, doi: 10.1126/sciadv.abd4044.

    Astrochemical models

    Using astrochemical models, Doddipatla et al. next studied how these lab outcomes could be transferred to the interstellar medium. The experimental findings provided vital criteria for the reaction to occur in low-temperature environments such as molecular clouds, where both methylidyne and styrene reactants exist. For instance, the methylidyne radicals can be generated within the internal ultraviolet (UV) photon field deep within molecular clouds. The scientists therefore conducted astrochemical simulations for the cold Taurus molecular cloud (TMC-1) using the Nautilus V1.1 code, to explore the efficiency of the MACA mechanism during indene formation in the interstellar medium. The results showed that while astronomically detecting indene in TMC-1 was challenging, it was technically feasible to conduct the experiments with high-spectral resolution and high sensitivity by using the Robert C. Byrd Green Bank Telescope (GBT) or the Atacama Large Millimeter/submillimeter Array (ALMA).

    Green Bank Radio Telescope, West Virginia, USA, now the center piece of the GBO, Green Bank Observatory, being cut loose by the NSF, supported by Breakthrough Listen.

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

    5
    TOP: Versatile conversion of a methyl (CH3) functional group of a PAH to the indene moiety via methylidyne radical reactions through vinyl (C2H3) substituted PAHs involving the novel methylidyne addition–cyclization–aromatization (MACA) mechanism. The waved lines indicate the incorporation within a PAH. BOTTOM: Indene carbon skeleton. Location of the carbon atoms within the styrene and methylidyne reactants and for the indene reaction product following addition to the vinyl (path A) and benzene moieties (paths B and C).Credit: Science Advances, doi: 10.1126/sciadv.abd4044.

    Outlook

    In this way, Srinivas Doddipatla and colleagues combined crossed molecular beams, electronic structure and astrochemical modeling to reveal the potential formation of indene across hot, carbon-rich stars and planetary nebulae, as well as in cold molecular clouds. The mechanism involved a simple, barrierless reaction based on the simplest organic radical methylidyne with styrene. The work represented an important step to understand the fundamental chemical processes forming indene and nonplanar polycyclic aromatic hydrocarbons (PAHs) in low-temperature environments in deep space. Given the crucial role that nonplanar PAHs play in the formation of carbonaceous cosmic dust particles commonly known as interstellar grains during the chemical evolution of the universe, understanding the elementary steps leading to cosmic dust particle formation will enhance the astrochemical awareness of our galaxy.

    See the full article here .

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    Please help promote STEM in your local schools.

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    About Science X in 100 words
    Science X™ is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004 (Physorg.com), Science X’s readership has grown steadily to include 5 million scientists, researchers, and engineers every month. Science X publishes approximately 200 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Science X community members enjoy access to many personalized features such as social networking, a personal home page set-up, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.
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  • richardmitnick 9:38 am on January 11, 2021 Permalink | Reply
    Tags: "Astrochemist brings search for extraterrestrial life to Center for Astrophysics" Clara Sousa-Silva, A good biosignature has a final characteristic: It has limited or accountable false positives., , Astrochemistry, , , , Phosphine has a unique spectral signature because the spectrum for phosphine is composed of the behavior of the bonds between hydrogen and phosphorus and that’s a very rare bond in gas molecules.,   

    From Harvard Gazette: “Astrochemist brings search for extraterrestrial life to Center for Astrophysics” Clara Sousa-Silva 

    Harvard University

    From Harvard Gazette

    January 4, 2021
    Alvin Powell

    Clara Sousa-Silva explores telltale biosignature gases on other planets.

    1
    Although the size and mass of Venus are similar to the Earth, its thick carbon-dioxide atmosphere has trapped heat so efficiently that the surface temperature usually exceeds 700 kelvins, hot enough to melt lead. Credit: SSV, MIPL, Magellan Team, NASA.

    In September, a team of astronomers announced a breathtaking finding: They had detected a molecule called phosphine high in the clouds of Venus, possibly indicating evidence of life [Nature Astronomy].

    That discovery shook the scientific establishment. Once thought of as Earth’s twin, Venus — though nearby and rocky — is now known to have a hellish environment, with a thick atmosphere that traps solar radiation, cranking surface temperatures high enough to melt metal, and accompanied by surface pressure akin to that thousands of feet below Earth’s ocean surface.

    But the detection, led by researchers from Cardiff University in Wales, the Massachusetts Institute of Technology, and the University of Manchester in England, was high in the atmosphere, where conditions are far more hospitable and the idea of microbial life more plausible. It was accomplished using spectroscopy, a method of determining the presence of different molecules in a planet’s atmosphere by analyzing how those molecules alter the light reflected from the planet. A key member of the team was fellow Clara Sousa-Silva, who had spent years studying the molecule’s spectroscopic signature and who believes that phosphine is a promising way to track the presence of extraterrestrial life.

    Sousa-Silva shifted her fellowship from MIT to the Center for Astrophysics | Harvard & Smithsonian and will spend the next two years advancing her work on biosignatures and life on other planets.

    She spoke with the Gazette about the recent discovery and what the future of the search for life may hold.

    Q&A
    Clara Sousa-Silva

    GAZETTE: You study biosignature gases, and your website says phosphine is your favorite. What is a biosignature gas and what’s so special about phosphine?

    SOUSA-SILVA: A biosignature gas is any gas in the planetary atmosphere that is produced by life. That by itself is not particularly interesting because molecules that can be produced by life can often be produced by many other things. So another question is: What is a good biosignature? And the answer to that also explains why phosphine is my favorite.

    A good biosignature isn’t just produced by life and released into an atmosphere. It is also able to survive in that atmosphere and be both detectable and distinguishable. So, if we’re looking at an atmosphere from far away, say from a different planet, and we detect an interesting molecule, that’s great. But maybe, because of low resolution in the instruments, lots of molecules look very similar to one another and the spectral signature also corresponds to a different molecule than one we thought we saw. So, you want a biosignature to be distinguishable.

    A good biosignature has a final characteristic: It has limited or accountable false positives. That means if it is produced by life, if it survives in the atmosphere, and you can detect it unambiguously, you still need to know if it was in fact produced by life or if it was accidentally produced by some other nonbiological process like photochemistry or volcanism. So, a good biosignature is all of these things: It is produced by life in large quantities and survives; it’s unambiguously detectable; and is unambiguously assigned to life.

    Famous biosignatures like oxygen and methane rank very well in the first few of these parameters. But methane, for example, looks an awful lot like every other hydrocarbon. And so knowing if you’re looking at methane versus a different molecule that also has carbons and hydrogens is quite hard. And even if you can unambiguously assign the thing you saw to methane, you don’t know if you can unambiguously assign it to life.

    Phosphine has a unique spectral signature, because the spectrum for phosphine is composed of the behavior of the bonds between hydrogen and phosphorus, and that’s a very rare bond in gas molecules. So phosphine is quite easy to distinguish, meaning it’s easy-ish to detect, and it is also produced by life. But it’s not produced by life in large quantities, so that’s a negative point for phosphine. But then, it’s so hard to produce without the intervention of life on rocky planets that it’s very low on false positives. I think phosphine is a well-balanced biosignature: produced in detectable quantities by life, being distinguishable, and having low false positives. That’s why it’s my favorite.

    2
    Clara Sousa-Silva, a fellow who grabbed headlines in September because of new findings of a potential signature for life on Venus, discusses that research. Credit: Kris Snibbe/Harvard.

    GAZETTE: Your site also says that phosphine is toxic to life that uses oxygen metabolism. So why is it a likely sign of life on Venus?

    SOUSA-SILVA: I don’t know if it’s likely. I wouldn’t dare put a probability on that. It is toxic to life on Earth that uses oxygen. And that is, obviously, us and everything we love. But lots of life on Earth does not rely on oxygen, and for the majority of time that life existed on Earth it also didn’t rely on oxygen. Granted, it wasn’t the most thrilling life. It wasn’t writing great works of literature, but it was nevertheless popular on Earth and seemingly very happy, thriving in forms that had no need for oxygen.

    The reason why phosphine on Venus, if it’s there, may signify life is more that we cannot explain it in any other way. We have no good explanation for the presence of phosphine on Venus, and we do know it can be produced by life. That doesn’t mean that’s what’s happening on Venus. That’s just, as extraordinary as it might sound, the best guess we have at this point.

    GAZETTE: Let’s talk specifically about the findings from September. What did you and your colleagues find on Venus?

    SOUSA-SILVA: It was an analysis of two separate observations done about 18 months apart. One was done with the JCMT, the James Clerk Maxwell Telescope, which is on Mauna Kea [in Hawaii].

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level.

    That observation has a tentative signal that could be assigned to phosphine. We then applied for time on ALMA [Atacama Large Millimeter/submillimeter Array in Chile], which is a much more powerful array of telescopes and which seemingly got a slightly stronger signal that also corresponded to phosphine.

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

    This is encouraging because the odds that a random signal will appear in the same place 18 months apart, using two different instruments, are very slim.

    The analysis was figuring out: One, is the signal real, because both of these instruments were collecting data very much at the limits of their capabilities. Two, if the signal is real, is the most plausible candidate phosphine rather than a different molecule? And three, if indeed the signal is real and it is phosphine, who or what is making it? Those are the three steps of the main article. This was about two years of work on top of my many years of work investigating phosphine as a biosignature.

    It took a long time and a large international team, including Anita [Richards, of the University of Manchester, U.K.] and Jane [Greaves, of Cardiff University (UK)]. Jane is the lead author of the paper that came out in September specifically extracting the signal from the data. Then lots of us were trying to figure out if the signal belongs to phosphine and if so, at what abundances. My contribution is that I know the pure spectroscopy of phosphine very well. My entire Ph.D. was dedicated to the spectroscopy of phosphine. So I was able to help figure out, if it was phosphine, what kind of abundances it was present in.

    I was also able to provide a list of other candidate molecules that could mimic the signal. The most promising one is phosphine, but the second-most-promising one is SO2 (sulphur dioxide), which would be a strange molecule to find in that location of Venus, but not anywhere near as strange as finding phosphine. So it was an important candidate to check. Then, if it is indeed phosphine and the signal is real, figuring out what is producing it was led by William Bains [at MIT]. It was also a large team, figuring out every process that might make phosphine and excluding a near-infinite list of negatives. It’s very, very hard to know if you’ve reached the end of that list.

    GAZETTE: So they’re working through the ways you might make phosphine that likely didn’t occur on Venus?

    SOUSA-SILVA: We’re trying to find an explanation, any explanation, and we did find a few methods that could produce small amounts of phosphine, but they were always quite trivial and always many orders of magnitude below what our estimates were for the signal detected in the clouds of Venus.

    GAZETTE: Is this discovery a warmup for finding phosphine and detecting biosignatures on planets around other stars?

    SOUSA-SILVA: I think it’s exactly a warmup for the search for life. It’s an excellent case study in the world of astrobiology.

    The odds that we find life beyond Earth from a booming, unambiguous, intelligent signal from the heavens is very slim. It’s likely, if we ever find life, that it is going to be something with quite a lot of uncertainty, and it will be really hard to even estimate that uncertainty. We won’t be able to say, “Oh, we found life with 80 percent certainty.” Those numbers are not ones we can do right now.

    What we can do is look at planets that have potentially habitable environments, look for molecules that can be associated with life, and then try to explain what’s going on there. We found a biomarker in a place that is potentially habitable. That’s a crucial first step, but it’s very far from the final step. We now need to figure out what other molecules would that biosphere produce? How will they interact with one another? How do we disentangle those behaviors from the spontaneous behaviors of a dead atmosphere?

    So, it’ll take a lot of work. We are very lucky to have Venus right next door so that we can use it as a lab. We can test all these theories in a way that we won’t be able to when we find a biomarker on an exoplanet, where there’s no hope of actually going in and probing the atmosphere to check. So this is a really important step.

    This has been reasonably controversial — and it should be — but we will have to do this many times. And every time we hope to be better prepared and have a better tool kit so that there’s less uncertainty. But it’ll take a long time before we can unambiguously confirm life elsewhere.

    GAZETTE: Before this discovery, Venus had been largely dismissed as a place for life because of its surface conditions. Your discovery has highlighted that a biosphere can be in places that may not immediately come to mind: high in the clouds where conditions are different. Is there a lesson here for thinking unconventionally when we evaluate places for life, especially since even here on Earth we’ve found life to be tough and enduring and in surprising places?

    SOUSA-SILVA: Life is very resilient and very resourceful on Earth and there’s no reason to think that’s some special characteristic of life on Earth rather than of life itself. We have ignored Venus because Venus is quite horrid to us. When we sent probes, they melted dramatically so we didn’t feel particularly welcome. It seems easier to imagine a place like Mars as habitable, even though actually there’s so little atmosphere and so little protection from the sun’s radiation that it’s really not an easily habitable surface.

    Mars is mostly uninhabitable, like Venus, just in a much quieter way. Mars will kill you, but it doesn’t melt you, so it feels more habitable, though I have no loyalty to either planet as a place to find life. This is hopefully going to help us think of habitability in a less anthropocentric way — or at least a less terra-centric way — and to think of habitability not just as a rocky planet with liquid water on the surface, but to think of subterranean habitats, moons of gas giants — something people already consider — and envelopes of an atmosphere as potentially habitable places in an otherwise uninhabitable planet.

    GAZETTE: What did you think when it became apparent that it might be life on Venus? Was that an exciting moment?

    SOUSA-SILVA: It was kind of a strange reversal. I had for years been working on this completely hypothetical investigation: If we found phosphine on a terrestrial planet what would it mean? I had concluded that because it has so few false positives on terrestrial planets that it could only mean life. I submitted the paper with this conclusion, and it was not controversial. The reviewers were fine with the idea — they had issues with other parts of the paper, but this didn’t bother them at all. No one cared because it was hypothetical: I was imagining this exotic, distant planet.

    When I was contacted by Jane, who had this tentative detection of phosphine on Venus, my not-so-controversial statement was now really extraordinary. And Venus is next door, so my hypothetical scenario became very concrete, very quickly. That was two years ago. We spent about a year and a half basically redoing and refining the analysis that we had done for my paper. This was, again, led by William Bains to try to figure out whether this is what happened on Venus. Venus is not your classic, potentially habitable exoplanet. It’s a pretty infernal place and maybe there phosphine could be made abiotically. So I never got to be as excited as I might at the first mention that phosphine had been found on a terrestrial planet. I expected this to happen hopefully before I die, but probably after I retire, not within months of submitting my hypothesis.

    I also immediately felt like I could not be trusted because I’m so biased. I’ve been working on phosphine for so long. I am a junior scientist without a permanent job. It would be so valuable to me for it to be life that I can’t be trusted to assess this accurately. So I was very careful to not get too excited. I had a strong glass of whiskey that evening, but that was it. Then I went and did the same work that we always do, which was to check every possible mechanism that can make phosphine, every possible molecule that can mimic the signal, and look again at everything I’ve done before and check for mistakes. It was nerve-racking to explore this expression of my prediction so nearby, so quickly.

    GAZETTE: Have you had a chance since the original paper was published?

    SOUSA-SILVA: Well, we did a good thing and paid a cost. Unlike a lot of observations of this kind, we published all our data and all our code. Everything was ready for people to come and tear it apart. So people did, which meant I never did get a little time off to enjoy it. It was great because they found a calibration mistake, and ALMA was able to rectify that, which allowed our team to reanalyze the data — they’re still doing it now. There was just way too much press and then way too much criticism, and I still haven’t taken time off.

    GAZETTE: About the scientific debate, how to you respond to the failure of other research groups to replicate the results?

    SOUSA-SILVA: This is the part of the work where I’m only tangentially involved, since I’m not doing any data reduction [of readings from Venus’ atmosphere]. This debate is a consequence of working at the edge of instrument capabilities, and the data are always going to be very noisy and delicate until we have better telescopes. Any discoveries made from these data, from the edges of our ability, are always going to be up for discussion. It’ll be nice when there’s a gold standard method for reducing these data, but there isn’t, so people disagree on the best way of extracting a signal without introducing spurious signals.

    The disagreement comes in a variety of forms, but the teams that didn’t replicate the results, don’t replicate the results in different ways. For example, the [Ignas] Snellen team [from Leiden University in the Netherlands] looked at the ALMA data before the calibration error had been corrected. I’m looking forward to seeing their revised analysis of the better data. The Villanueva team [led by Geronimo Villanueva at the NASA-Goddard Space Flight Center] that looked at both the ALMA data and the JCMT data, did find signals in the JCMT data, which, of course, begs the question of “Where does the signal go in the ALMA data?”

    They do disagree on the source of the JCMT signal, though. SO2 [sulfur dioxide], our second-most-plausible candidate, is their first-most-plausible candidate. And that is an even more complicated question of how you choose between two molecules that can simulate the same signal at these resolutions. Our team’s argument is that the SO2 [spectra] is a little off — you would expect SO2 to show up in different areas of the white bandpass. There also isn’t enough SO2 to justify the signal, so phosphine would need to complement the size of the signal. It’s a difficult argument to make — and we’re at the edge of the statistical significance of the signal — but it’s a totally valid argument.

    Then there’s the archival Pioneer data that was revisited and that they think could correspond to phosphine. It’s hard to bring all of this data to a place where they agree with one another, sadly, because people want to know the truth — I do, too. But the only real conclusion we have is that we don’t know Venus well enough, and we need more data. We need more observations that are not at the edge of instrument capabilities so that there’s no ambiguity in what we’re looking at.

    GAZETTE: Let’s talk a little bit about what you’ll be doing here at Harvard. You’ve been a fellow at MIT. Is the fellowship split between there and here?

    SOUSA-SILVA: No, I moved it. I am 100 percent Harvard — for the last two months, I think. It’s very new.

    GAZETTE: Who will you be working with and what will you be doing?

    SOUSA-SILVA: The 51 Pegasi b Fellowship is a wonderful three-year prize fellowship that is provided by the Heising-Simons Foundation. I did one year at MIT, and I’ve moved to Harvard for the last two years of the fellowship. My host is Dave Charbonneau — part of the reason I moved to Harvard is because of the expertise he has — and the team that surrounds him — on exoplanet atmospheres. There’s also the HITRAN [High resolution Transmission molecular absorption database] group, led by Iouli Gordon — and previously, Larry Rothman — who are world leaders in spectroscopic databases, which is the bread and butter of my work. So that combination of expertise made Harvard perfect.

    GAZETTE: Are you doing most of your work out of your home now or are you able to commute to the CfA physically?

    SOUSA-SILVA: No, I don’t even know where my office is yet. I would love to be commuting to the CfA, but because my work can be done remotely, it shall be done remotely.

    GAZETTE: Are you continuing to work on phosphine and Venus or are you moving on to other topics?

    SOUSA-SILVA: I’ll give it the same percentage of my time as I have in the past. Phosphine is very much my expert molecule, but 50 percent of my work is pushing against the notion of looking for single indicators of life. Because unless we get a radio signal in prime numbers or an unambiguous sign of CFCs [chlorofluorocarbons] or other really complex pollutants, we are going to need more than one molecule; we’re going to need a whole array of molecules that together paint the picture of a biosphere with all its complexity and interactions.

    So most of my work is trying to provide a tool kit that can detect every molecule that could potentially be in a habitable atmosphere. I started the work at MIT. They had come up with a list of all the possible molecules that could form in the context of a biosphere: 16,367. I know that number because I’ve been working on it for so long.

    Out of those thousands, we have spectra of some quality — and some of them are rough — for less than 4 percent of them. For the majority of molecules, we don’t even have even a crude ability to detect them. So most of my work is trying to simulate that spectra so we have at least some idea of what these molecules look like. That’s the connection to HITRAN. They have extremely high accuracy and extremely careful data on a handful of molecules, a little over 50. That is wonderful, but only a small dent in the list of 16,000-plus.

    I created a small program called RASCALL, for Rapid Approximate Spectral Calculations for All. The idea is to make really rough, very quick spectra for all of these molecules, and then build on it. Without RASCALL, the way I did my phosphine spectra took me a bit over four years and many extremely expensive supercomputers. I can’t repeat that for the 16,000 molecules. I calculated that it would take me over 62,000 years. I’m trying to shorten that timescale into something that resembles my lifetime, and that’s where RASCALL comes in.

    GAZETTE: Folks like you will be helping answer an interesting question in the decades to come: whether life is something rare or whether it’s not really that rare after all. It seems the thinking on that has been shifting in recent decades.

    SOUSA-SILVA: I do like that the shift is happening and that people are thinking that life is more common. I’m hoping that shift will go so far as thinking that life is not that special. It’s just an inevitable occurrence in a variety of contexts. If it can appear in places as different as Earth and Venus, which are at first glance similar because of their size and location but otherwise very different, then it must be extremely common because it would be the height of hubris to think that only the solar system can have life, but it has arisen twice in totally different environments.

    That seems really implausible. The sun is average, rocky planets are extremely common, the molecular cloud that formed the solar system was not special. Life on Earth came to be in a huge diversity of forms, and life changed Earth’s atmosphere many times. We only have one planet where we know life existed, but Earth has been many planets, which is something an astronomer colleague of mine, Sarah Rugheimer, likes to say. We have quite a lot of data points that basically show that life is pretty good at making itself happen in many ways throughout history.

    See the full article here .

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    Harvard University campus
    Harvard University is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.

    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

     
  • richardmitnick 9:40 am on May 27, 2020 Permalink | Reply
    Tags: "The 'Where’s Waldo?' of Astrochemistry", , , Astrochemistry, The Missing Molecule-Propadienone (CH2CCO)   

    From astrobites: “The ‘Where’s Waldo?’ of Astrochemistry” 

    26 May 2020

    1
    Searching for molecules in space can sometimes feel like a Where’s Waldo hunt — but finding the missing pieces helps us better understand our universe. [NASA/Jenny Mottar]

    Title: The Case of H2C3O Isomers, Revisited: Solving the Mystery of the Missing Propadienone
    Authors: Christopher N. Shingledecker et al.
    First Author’s Institution: Center for Astrophysics Studies Max Plank Institute for Extraterrestrial Physics & Institute for Theoretical Chemistry at the University of Stuttgart

    MPG Institute for Astrophysics


    Status: Published in ApJ

    Finding and Making Molecules

    Looking for different chemicals in space is a lot like searching for Waldo in the infamous search and find series “Where’s Wally?” Only imagine that the search and find page is light years away from you and all you have is a flashlight.

    3

    As our knowledge and understanding of chemical evolution in space grows, astronomers are seeking the detection of more and more complex organic molecules (COMs). Molecules that could lead to the production of life (like prebiotic molecules that may eventually form DNA) and other larger COMs are rather difficult to detect, so we often use theoretical calculations to predict the evolution and abundance of these larger molecules.

    Chemical models commonly use kinetics, how energy changes over as a reaction progresses, to determine the rate at which chemical reactions occur, and thus the rate at which more complex molecules form and how abundances vary over time. Kinetics tells us that chemical reactions typically have an energy barrier to get from reactants to products. However, space is so cold that there isn’t enough energy available to overcome energy barriers (imagine pushing a 500 pound boulder over the top of Mount Everest). So, we assume that only barrier-less reactions can occur in space. There is a noteworthy exception of ultra hot regions like HII regions, supernovae, and such, where temperatures are high enough to overcome reaction barriers.

    4
    Most chemical reactions must overcome a reaction barrier to get from reactants to products, but most astronomical settings aren’t warm enough to provide the energy necessary to overcome these barriers. [Libretexts]

    One of the most important aspects of theoretical research is matching observational data. If theoretical models using activation barriers and chemical kinetics are not able to match observations, then that usually indicates that there is a physical or chemical process that we don’t know about.

    The Missing Molecule

    In the last decade, one important molecule that has alluded astronomers is CH2CCO, or propadienone. CH2CCO is actually one of three different molecules that can be made from two hydrogen atoms, three carbon atoms, and one oxygen atom (H2C3O). These are known as structural isomers, meaning they’re made up of all the same atoms, but the atoms can be arranged differently to make different molecules.

    5
    The three molecules we can make from H2C3O. Each isomer is made up of the same components, just as the three “Waldo” cartoons above them. However, each H2C3O isomer is put together in a different order, similar to the “Waldo isomers.” Each Waldo is made up of the same colors, but the colors are arranged in different orders.
    [H2C3O isomer structures: Hudson & Gerakines 2019; “Waldo”: Waldo Wiki]

    Propadienone (CH2CCO) is the most stable isomer of H2C3O, meaning CH2CCO has the lowest ground state energy and the H2C3O atoms are “happiest” in the CH2CCO configuration. According the the minimum energy principle, which uses thermodynamics rather than kinetics to predict chemical evolution, CH2CCO should be the most abundant of the three isomers, since it is the most stable of the three. Despite observational efforts and archival data searches, no one has been able to detect CH2CCO in space even though the other two H2C3O isomers have been detected. As the minimum energy principle states that CH2CCO should be detectable as well, this disagreement between observations and theory challenged the minimum energy principle and questioned the validity of relying on kinetics for chemical models.

    Where’s CH2CCO?

    So, where is CH2CCO? As it turns out, we still haven’t detected it in space. However, today’s paper uses theoretical calculations to find “where” CH2CCO is hiding. The authors map reactions associated with the H2C3O isomers using density functional theory (DFT). DFT uses quantum mechanics and kinetics to determine the most stable structures of molecules and their associated energies. CH2CCO can react with two hydrogen atoms to form propenal (CH2CHCHO). The process of adding a single H atom, or a proton, is a common reaction known as hydrogen addition. CH2CCO undergoes two hydrogen additions to form CH2CHCHO, both of which were found to be barrier-less reactions.

    6
    Left: Reaction diagram from today’s paper showing that adding a hydrogen to CH2CCO is a barrier-less reaction, and thus able to occur in space. Right: Hydrogen additions to CH2CCO to form CH2CHCHO. Each reaction adds a single H atom to the carbon chain. Note the black dots are single, unpaired electrons (radicals). [Shingledecker et al. 2019]

    Interestingly enough, hydrogen addition to the second most stable H2C3O isomer, propynal (HCCCHO), is found to have a reaction barrier. Thus propynal is able to persist in molecular clouds, while CH2CCO is converted to CH2CHCHO. These findings are consistent with both previous experimentation and observations of the Sagittarius B2 molecular cloud, where the two less stable H2C3O isomers and CH2CHCHO were detected, but CH2CCO was not.

    Today’s paper shows that the “missing” molecule propadienone (CH2CCO) was never actually missing; it was just masquerading as CH2CHCHO. This discovery is important, since it shows us that kinetic theory and observations of CH2CCO are actually in agreement, rather than disagreement. Additionally, today’s paper confirms the validity of using chemical kinetics and reaction barriers (or lack of barriers) to predict chemical evolution in astronomical settings.

    Sometimes search and finds, like finding molecules in astronomical settings, can be difficult — but ultimately, finding the missing pieces helps us better understand our universe.

    Now that we’ve found CH2CCO, did you find Waldo in the first figure?

    See the full article here .


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    What do we do?

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

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

     
  • richardmitnick 11:38 am on October 3, 2019 Permalink | Reply
    Tags: "Brett McGuire searches space for the chemistry of life", Astrochemistry, , , , , , , ,   

    From Science News: “Brett McGuire searches space for the chemistry of life” 

    From Science News

    October 2, 2019
    Lisa Grossman

    Cosmic molecules may point to the origins of carbon-based life.

    In a different reality, space might smell like almonds. After all, scientists surveying the chemicals in the cosmos have found benzonitrile; just a bit of the compound would fill your nostrils with a bitter almond scent.

    But our cosmos is too vast. “Space smells like nothing,” says astrochemist Brett McGuire. “There’s not enough to get an actual whiff.”

    2
    Astrochemist Brett McGuire combines skills in chemistry and astronomy to search for complex molecules in space. Courtesy of B. McGuire

    McGuire, 32, of the National Radio Astronomy Observatory in Charlottesville, Va., confirmed the presence of benzonitrile in a dark cloud in the Milky Way. He also discovered some of the other most complex molecules in space to date. By figuring out which molecules are out there, he and others hope to learn how the organic chemistry that undergirds all life on Earth — and perhaps anywhere else in the universe — gets started in space.

    McGuire got his start in space as an undergraduate chemistry major at the University of Illinois at Urbana-Champaign. During a talk, Ben McCall, now a sustainability expert at the University of Dayton in Ohio, explained what he does for a living. He said something like, “I blow shit up, torture it with lasers and then I look for it in space,” McGuire recalls.

    Enough said. McGuire spent that summer working in McCall’s lab, building a spectrometer to study how hydrogen gas, H2, reacts with H3+ — three hydrogen atoms with only two electrons. Some of McCall’s research included zapping gases of simple molecules with electricity — “an actual miniature lightning bolt,” McGuire says — to force atoms to recombine into new compounds that can’t be bought in a bottle.

    “Brett was a very precocious young scientist,” McCall says. “This was the only time I’ve had a student who really started a new instrument from scratch as an undergrad.”

    3
    The discovery of benzonitrile in a dust cloud in the Milky Way suggests that complex molecules can form from the buildup of smaller molecules in space. (Carbon is black, hydrogen white and nitrogen blue.) Ben Mills and Jynto/Wikimedia Commons

    Because space is so big and mostly empty, at least by Earth standards, it can take millions of years for two molecules flying around like billiard balls to get close enough to interact. “But it’s not just neutral billiard balls out there,” McGuire says. A charged molecule, like H3+, which has been discovered in interstellar space, can pull other molecules closer. “More or less all chemistry in space can trace itself back to H3+ at some point.”

    And all that chemistry includes some tantalizingly lifelike stuff. In 2016, McGuire and colleagues reported discovering propylene oxide in a gas cloud within the Milky Way.

    4
    MOLECULE CLUE A gas cloud (Sagittarius B2) near the center of the galaxy (Sagittarius A*) is loaded with propylene oxide, a molecule that comes in mirror-image configurations. B. Saxton, NRAO/AUI/NSF from data provided by N.E. Kassim, Naval Research Laboratory, Sloan Digital Sky Survey.

    That was the first molecule seen in space that, like the amino acids that make up proteins and are essential to life on Earth, has two forms that are mirror images of each other. Large rings of carbon and hydrogen, called polycyclic aromatic hydrocarbons, or PAHs, have also been spotted around dead or dying stars — though it’s been hard to tell how many carbons and hydrogens the PAHs contain.

    PAHs are thought to be the seeds of dust, planets and organic chemistry in our galaxy and other galaxies, McGuire says. So how do they form? “How do you go from H3+ to things that literally click together to make the building blocks of life?” he asks.

    The work of enumerating what’s out there mostly takes place in a lab on Earth. McGuire injects a puff of gas of the molecule he’s interested in into a large vacuum chamber, where the low temperature and pressure make the gas expand. Then he hits the gas with a pulse of intense microwave or radio radiation, sending the molecules tumbling. As they tumble, the molecules emit photons at a specific frequency. That light signature, called the molecule’s rotational spectrum, is what McGuire looks for when he searches for those molecules in space.

    Once McGuire knows the molecular fingerprint he’s after, he turns to radio telescopes to find the same print in space. Many scientists focus on one branch of this process or the other, the laboratory spectroscopy or the interstellar astronomy; only a few have expertise in both. “Brett is one of those very few people,” McCall says.

    To sniff almonds in space, McGuire and colleagues focused the Robert C. Byrd Green Bank Telescope in West Virginia on TMC-1, a dark cloud about 450 light-years from Earth “where maybe there are stars that are considering starting to form,” McGuire says. Forty hours of observing confirmed that benzonitrile, a benzene ring with a cyanide molecule stuck on the end, was there [Science].

    Green Bank Radio Telescope, West Virginia, USA, now the center piece of the GBO, Green Bank Observatory, being cut loose by the NSF

    6
    Scientists have detected complex molecules in TMC-1, a stellar nursery in the Milky Way. The cloud lacks big, bright stars, and its dust grains glow only faintly (shown in orange). ESO

    Lately, McGuire and colleagues are closing in on a bigger prize: specific PAHs in the space between stars. Knowing the makeup of PAHs in space will help reveal how they click together from smaller molecules, McGuire says. Finding these molecules would show that advanced chemistry is happening, in some cases before stars begin forming.

    Benzonitrile and the more complex molecules it hints at are “the first clear marker” of carbon-based chemistry in space, says Ryan Fortenberry, an astrochemist at the University of Mississippi in Oxford who wasn’t involved in the benzonitrile finding. “Before this, we were just kind of wandering around in the wilderness,” Fortenberry says. “Now we have found the trail.”

    See the full article here .


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  • richardmitnick 5:55 pm on March 13, 2019 Permalink | Reply
    Tags: Astrochemistry, , , , , , Trihydrogen or H3+ is acknowledged by scientists as the molecule that made the universe.   

    From Michigan State University: “Understanding and controlling the molecule that made the universe” 

    Michigan State Bloc

    From Michigan State University

    March 13, 2019

    Layne Cameron
    Media Communications office
    (517) 353-8819
    cell: (765) 748-4827
    Layne.Cameron@cabs.msu.edu

    Marcos Dantus
    Chemistry office
    (517) 355-9715
    dantus@msu.edu

    Trihydrogen, or H3+, is acknowledged by scientists as the molecule that made the universe. In recent issues of Nature Communications and the Journal of Chemical Physics, Michigan State University researchers employed high-speed lasers to shine a spotlight on the mechanisms that are key in H3+ creation and its unusual chemistry.

    H3+ is prevalent in the universe, the Milky Way, gas giants and the Earth’s ionosphere. It’s also being created and studied in the lab of Marcos Dantus, University Distinguished Professor in chemistry and physics. Using ultrafast lasers – and technology invented by Dantus – a team of scientists is beginning to understand the chemistry of this iconic molecule.

    “Observing how roaming H2 molecules evolve to H3+ is nothing short of astounding,” Dantus said. “We first documented this process using methanol; now we’ve been able to expand and duplicate this process in a number of molecules and identified a number of new pathways.”

    Astrochemists see the big picture, observing H3+ and defining it through an interstellar perspective. It’s created so fast ­– in less time than it takes a bullet to cross an atom – that it is extremely difficult to figure out how three chemical bonds are broken and three new ones are formed in such a short timescale.

    That’s when chemists using femtosecond lasers come into play. Rather than study the stars using a telescope, Dantus’ team literally looks at the small picture. The entire procedure is viewed at the molecular level and is measured in femtoseconds – 1 millionth of 1 billionth of a second. The process the team views takes between 100 and 240 femtoseconds. Dantus knows this because the clock starts when he fires the first laser pulse. The laser pulse then “sees” what’s happening.

    The two-laser technique revealed the hydrogen transfer, as well as the hydrogen-roaming chemistry, that’s responsible for H3+ formation. Roaming mechanisms briefly generate a neutral molecule (H2) that stays in the vicinity and extracts a third hydrogen molecule to form H3+. And it turns out there’s more than one way it can happen. In one experiment involving ethanol, the team revealed six potential pathways, confirming four of them.

    Since laser pulses are comparable to sound waves, Dantus’ team discovered a “tune” that enhances H3+ formation and one that discourages formation. When converting these “shaped” pulses to a slide whistle, successful formation happens when the note starts flats, rises slightly and finishes with a downward, deeper dive. The song is music to the ears of chemists who can envision many potential applications for this breakthrough.

    “These chemical reactions are the building blocks of life in the universe,” Dantus said. “The prevalence of roaming hydrogen molecules in high-energy chemical reactions involving organic molecules and organic ions is relevant not only for materials irradiated with lasers, but also materials and tissues irradiated with x-rays, high energy electrons, positrons and more.”

    This study reveals chemistry that is relevant in terms of the universe’s formation of water and organic molecules. The secrets it could unlock, from astrochemical to medical, are endless, he added.

    MSU scientists who contributed to the Nature Communications paper included Nagitha Ekanayake, Muath Nairat, Nicholas Weingartz, Benjamin Farris, Benjamin Levine and James Jackson. Researchers from Kansas State University also contributed to this study.

    MSU scientists who contributed to the Journal of Chemical Physics paper included Ekanayake, Nairat, Matthew Michie, Weingartz and Levine.

    This research was funded by the Department of Energy and the National Science Foundation.

    (Note to media: Please include link to the original papers in online coverage: https://www.nature.com/articles/s41467-018-07577-0; https://aip.scitation.org/doi/10.1063/1.5070067)

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Michigan State Campus

    Michigan State University (MSU) is a public research university located in East Lansing, Michigan, United States. MSU was founded in 1855 and became the nation’s first land-grant institution under the Morrill Act of 1862, serving as a model for future land-grant universities.

    MSU pioneered the studies of packaging, hospitality business, plant biology, supply chain management, and telecommunication. U.S. News & World Report ranks several MSU graduate programs in the nation’s top 10, including industrial and organizational psychology, osteopathic medicine, and veterinary medicine, and identifies its graduate programs in elementary education, secondary education, and nuclear physics as the best in the country. MSU has been labeled one of the “Public Ivies,” a publicly funded university considered as providing a quality of education comparable to those of the Ivy League.

    Following the introduction of the Morrill Act, the college became coeducational and expanded its curriculum beyond agriculture. Today, MSU is the seventh-largest university in the United States (in terms of enrollment), with over 49,000 students and 2,950 faculty members. There are approximately 532,000 living MSU alumni worldwide.

     
  • richardmitnick 12:29 pm on February 7, 2019 Permalink | Reply
    Tags: , Astrochemistry, , , “When we look at the information ALMA has provided we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chloride coming from the disk", , , , Liberal Sprinkling of Salt Discovered around a Young Star, , Orion Source I, , The chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, The Orion Molecular Cloud 1   

    From ALMA: “Liberal Sprinkling of Salt Discovered around a Young Star” 

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

    From ALMA

    7 February, 2019

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory Santiago – Chile
    Phone: +56 2 2467 6258
    Cell phone: +56 9 7587 1963
    Email: valeria.foncea@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
    Email: cblue@nrao.edu

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: calum.turner@eso.org

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

    1
    Artist impression of Orion Source I, a young, massive star about 1,500 light-years away. New ALMA observations detected a ring of salt — sodium chloride, ordinary table salt — surrounding the star. This is the first detection of salts of any kind associated with a young star. The blue region (about 1/3 the way out from the center of the disk) represents the region where ALMA detected the millimeter-wavelength “glow” from the salts. Credit: NRAO/AUI/NSF; S. Dagnello

    2
    ALMA image of the salty disk surrounding the young, massive star Orion Source I (blue ring). It is shown in relation to the Orion Molecular Cloud 1, a region of explosive starbirth. The background near infrared image was taken with the Gemini Observatory. Credit: ALMA (NRAO/ESO/NAOJ); NRAO/AUI/NSF; Gemini Observatory/AURA

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

    A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula.

    “It’s amazing we’re seeing these molecules at all,” said Adam Ginsburg, a Jansky Fellow of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and lead author of a paper accepted for publication in The Astrophysical Journal. “Since we’ve only ever seen these compounds in the sloughed-off outer layers of dying stars, we don’t fully know what our new discovery means. The nature of the detection, however, shows that the environment around this star is very unusual.”

    To detect molecules in space, astronomers use radio telescopes to search for their chemical signatures – telltale spikes in the spread-out spectra of radio and millimeter-wavelength light. Atoms and molecules emit these signals in several ways, depending on the temperature of their environments.

    The new ALMA observations contain a bristling array of spectral signatures – or transitions, as astronomers refer to them – of the same molecules. To create such strong and varied molecular fingerprints, the temperature differences where the molecules reside must be extreme, ranging anywhere from 100 kelvin to 4,000 kelvin (about -175 Celsius to 3700 Celsius). An in-depth study of these spectral spikes could provide insights about how the star is heating the disk, which would also be a useful measure of the luminosity of the star.

    “When we look at the information ALMA has provided, we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chloride coming from the disk. That is both shocking and exciting,” said Brett McGuire, a chemist at the NRAO in Charlottesville, Virginia, and co-author on the paper.

    The researchers speculate that these salts come from dust grains that collided and spilled their contents into the surrounding disk. Their observations confirm that the salty regions trace the location of the circumstellar disk.

    “Usually when we study protostars in this manner, the signals from the disk and the outflow from the star get muddled, making it difficult to distinguish one from the other,” said Ginsburg. “Since we can now isolate just the disk, we can learn how it is moving and how much mass it contains. It also may tell us new things about the star.”

    The detection of salts around a young star is also of interest to astronomers and astrochemists because some of constituent atoms of salts are metals – sodium and potassium. This suggests there may be other metal-containing molecules in this environment. If so, it may be possible to use similar observations to measure the amount of metals in star-forming regions. “This type of study is not available to us at all presently. Free-floating metallic compounds are generally invisible to radio astronomy,” noted McGuire.

    The salty signatures were found about 30 to 60 astronomical units (AU, or the average distance between the Earth and the Sun) from the host stars. Based on their observations, the astronomers infer that there may be as much as one sextillion (a one with 21 zeros after it) kilograms of salt in this region, which is roughly equivalent to the entire mass of Earth’s oceans.

    “Our next step in this research is to look for salts and metallic molecules in other regions. This will help us understand if these chemical fingerprints are a powerful tool to study a wide range of protoplanetary disks, or if this detection is unique to this source,” said Ginsburg. “In looking to the future, the planned Next Generation VLA would have the right mix of sensitivity and wavelength coverage to study these molecules and perhaps use them as tracers for planet-forming disks.”

    Orion Source I formed in the Orion Molecular Cloud I, a region of explosive starbirth previously observed with ALMA. “This star was ejected from its parent cloud with a speed of about 10 kilometers per second around 550 years ago,”1 said John Bally, an astronomer at the University of Colorado and co-author on the paper. “It is possible that solid grains of salt were vaporized by shock waves as the star and its disk were abruptly accelerated by a close encounter or collision with another star. It remains to be seen if salt vapor is present in all disks surrounding massive protostars, or if such vapor traces violent events like the one we observed with ALMA.”

    1. Light from this object took about 1,500 years to reach Earth. Astronomers are seeing it as if looking through that window of time, which reveals how it looked 550 years after it was ejected from its stellar nursery.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

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

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

    NRAO Small
    ESO 50 Large
    NAOJ

     
    • iptv 1:43 am on February 13, 2019 Permalink | Reply

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