Tagged: Astronomy Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 4:17 pm on September 29, 2016 Permalink | Reply
    Tags: Astronomy, , LMC P3, , , Record-breaking Binary in Galaxy Next Door   

    From NASA Goddard and Fermi: “NASA’s Fermi Finds Record-breaking Binary in Galaxy Next Door” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    NASA Fermi Banner


    Fermi

    Sept. 29, 2016
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Using data from NASA’s Fermi Gamma-ray Space Telescope and other facilities, an international team of scientists has found the first gamma-ray binary in another galaxy and the most luminous one ever seen. The dual-star system, dubbed LMC P3, contains a massive star and a crushed stellar core that interact to produce a cyclic flood of gamma rays, the highest-energy form of light.

    “Fermi has detected only five of these systems in our own galaxy, so finding one so luminous and distant is quite exciting,” said lead researcher Robin Corbet at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Gamma-ray binaries are prized because the gamma-ray output changes significantly during each orbit and sometimes over longer time scales. This variation lets us study many of the emission processes common to other gamma-ray sources in unique detail.”

    These rare systems contain either a neutron star or a black hole and radiate most of their energy in the form of gamma rays. Remarkably, LMC P3 is the most luminous such system known in gamma rays, X-rays, radio waves and visible light, and it’s only the second one discovered with Fermi.


    Access mp4 video here .
    Dive into the Large Magellanic Cloud and see a visualization of LMC P3, an extraordinary gamma-ray binary system discovered by NASA’s Fermi Gamma-ray Space Telescope. Credits: NASA’s Goddard Space Flight Center/Scott Wiessinger, producer

    A paper describing the discovery will appear in the Oct. 1 issue of The Astrophysical Journal and is now available online, and you an see the full science team.

    LMC P3 lies within the expanding debris of a supernova explosion located in the Large Magellanic Cloud (LMC), a small nearby galaxy about 163,000 light-years away.

    Large Magellanic Cloud. Adrian Pingstone  December 2003
    Large Magellanic Cloud. Adrian Pingstone December 2003

    In 2012, scientists using NASA’s Chandra X-ray Observatory found a strong X-ray source within the supernova remnant and showed that it was orbiting a hot, young star many times the sun’s mass.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    The researchers concluded the compact object was either a neutron star or a black hole and classified the system as a high-mass X-ray binary (HMXB).

    In 2015, Corbet’s team began looking for new gamma-ray binaries in Fermi data by searching for the periodic changes characteristic of these systems. The scientists discovered a 10.3-day cyclic change centered near one of several gamma-ray point sources recently identified in the LMC. One of them, called P3, was not linked to objects seen at any other wavelengths but was located near the HMXB. Were they the same object?

    3
    Observations from Fermi’s Large Area Telescope (magenta line) show that gamma rays from LMC P3 rise and fall over the course of 10.3 days. The companion is thought to be a neutron star. Illustrations across the top show how the changing position of the neutron star relates to the gamma-ray cycle. Credits: NASA’s Goddard Space Flight Center

    To find out, Corbet’s team observed the binary in X-rays using NASA’s Swift satellite, at radio wavelengths with the Australia Telescope Compact Array near Narrabri and in visible light using the 4.1-meter Southern Astrophysical Research Telescope on Cerro Pachón in Chile and the 1.9-meter telescope at the South African Astronomical Observatory near Cape Town.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    CSIRO Australian Telescope Compact Array at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney
    CSIRO Australian Telescope Compact Array at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney, AU

    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón - IV Región - Chile, at 2,700 meters (8,775 feet)
    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón – IV Región – Chile

    4
    1.9-meter Radcliffe telescope at the South African Astronomical Observatory near Cape Town

    The Swift observations clearly reveal the same 10.3-day emission cycle seen in gamma rays by Fermi. They also indicate that the brightest X-ray emission occurs opposite the gamma-ray peak, so when one reaches maximum the other is at minimum. Radio data exhibit the same period and out-of-phase relationship with the gamma-ray peak, confirming that LMC P3 is indeed the same system investigated by Chandra.

    “The optical observations show changes due to binary orbital motion, but because we don’t know how the orbit is tilted into our line of sight, we can only estimate the individual masses,” said team member Jay Strader, an astrophysicist at Michigan State University in East Lansing. “The star is between 25 and 40 times the sun’s mass, and if we’re viewing the system at an angle midway between face-on and edge-on, which seems most likely, its companion is a neutron star about twice the sun’s mass.” If, however, we view the binary nearly face-on, then the companion must be significantly more massive and a black hole.

    5
    LMC P3 (circled) is located in a supernova remnant called DEM L241 in the Large Magellanic Cloud, a small galaxy about 163,000 light-years away. The system is the first gamma-ray binary discovered in another galaxy and is the most luminous known in gamma rays, X-rays, radio waves and visible light.

    Both objects form when a massive star runs out of fuel, collapses under its own weight and explodes as a supernova. The star’s crushed core may become a neutron star, with the mass of half a million Earths squeezed into a ball no larger than Washington, D.C. Or it may be further compacted into a black hole, with a gravitational field so strong not even light can escape it.

    The surface of the star at the heart of LMC P3 has a temperature exceeding 60,000 degrees Fahrenheit (33,000 degrees Celsius), or more than six times hotter than the sun’s. The star is so luminous that pressure from the light it emits actually drives material from the surface, creating particle outflows with speeds of several million miles an hour.

    In gamma-ray binaries, the compact companion is thought to produce a “wind” of its own, one consisting of electrons accelerated to near the speed of light. The interacting outflows produce X-rays and radio waves throughout the orbit, but these emissions are detected most strongly when the compact companion travels along the part of its orbit closest to Earth.

    Through a different mechanism, the electron wind also emits gamma rays. When light from the star collides with high-energy electrons, it receives a boost to gamma-ray levels. Called inverse Compton scattering, this process produces more gamma rays when the compact companion passes near the star on the far side of its orbit as seen from our perspective.

    Prior to Fermi’s launch, gamma-ray binaries were expected to be more numerous than they’ve turned out to be. Hundreds of HMXBs are cataloged, and these systems are thought to have originated as gamma-ray binaries following the supernova that formed the compact object.

    “It is certainly a surprise to detect a gamma-ray binary in another galaxy before we find more of them in our own,” said Guillaume Dubus, a team member at the Institute of Planetology and Astrophysics of Grenoble in France. “One possibility is that the gamma-ray binaries Fermi has found are rare cases where a supernova formed a neutron star with exceptionally rapid spin, which would enhance how it produces accelerated particles and gamma rays.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

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

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

    NASA Goddard campus
    NASA/Goddard Campus

    NASA image

     
  • richardmitnick 2:30 pm on September 29, 2016 Permalink | Reply
    Tags: , ALMA Discovers Hidden Spiral Arms Embracing a Young Star, Astronomy, , ,   

    From ALMA: “ALMA Discovers Hidden Spiral Arms Embracing a Young Star” 

    ALMA Array

    ALMA

    29 September 2016
    Valeria Foncea

    Education and Public Outreach Officer

    Joint ALMA Observatory

    Santiago, Chile

    Tel: +56 2 467 6258

    Cell: +56 9 75871963
    Email: valeria.foncea@alma.cl

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

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Masaaki Hiramatsu

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

    Tel: +81 422 34 3630

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

    1
    ALMA peered into the Ophiuchus star-forming region to study the protoplanetary disk around the young star Elias 2-27. Astronomers discovered a striking spiral pattern in the disk. This feature is the product of density waves – gravitational perturbations in the disk. Credit: L. Pérez (MPIfR), B. Saxton (NRAO/AUI/NSF), ALMA (ESO/NAOJ/NRAO), NASA/JPL Caltech/WISE Team.

    Swirling around the young star Elias 2-27, astronomers discovered a stunning spiral-shape pinwheel of dust. This striking feature, seen with the Atacama Large Millimeter/submillimeter Array (ALMA), is the product of density waves – gravitational perturbations in the disk that produce sweeping arms reminiscent of a spiral galaxy, but on a much smaller scale.

    “These observations are the first direct evidence for density waves in a protoplanetary disk,” said Laura Perez, an astronomer with the Max Planck Institute for Radio Astronomy in Bonn, Germany, and lead author on a paper published in the journal Science.

    Previously, astronomers noted compelling spiral features on the surfaces of protoplanetary disks, but it was unknown if these same spiral patterns also emerged deep within the disk where planet formation takes place. ALMA, for the first time, was able to peer deep into the mid-plane of a disk and discovered the clear signature of spiral density waves.

    Nearest to the star, ALMA found a familiar flattened disk of dust, which extends past the orbit of Neptune in our own solar system. Beyond that point, ALMA detected a narrow band with significantly less dust, which may be indicative of a planet in formation. Springing from the outer edge of this gap are two sweeping spiral arms that extend more than 10 billion kilometers away from their host star.

    2
    ALMA discovered sweeping spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. This spiral feature was produced by density waves – gravitational perturbations in the disk. Credit: B. Saxton (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

    Finding density waves at these extreme distances may have implications for planet-formation theory, Perez notes. The standard picture of planet formation begins with small planetesimals coming together under gravity. In the outer reaches of a disk, where there is a dearth of planetesimals, gravitational instabilities may also lead directly to the formation of a planet. ALMA’s detection of spiral density waves may be evidence that such a process is taking place.

    Elias 2-27 is located approximately 450 light-years from Earth in the Ophiuchus star-forming complex. Even though it contains only about half the mass of our Sun, this star has an unusually massive protoplanetary disk. The star is estimated to be at least one million years old and still encased in its parent molecular cloud, obscuring it from optical telescopes.

    “There are still questions of how these features form. Perhaps they are the result of a newly forged planet interacting with the protoplanetary disk or simply gravitational instabilities driven by the shear mass of the disk,” said Perez. “ALMA will further dissect this and other similar disks in an upcoming large program, helping astronomers understand the seemingly chaotic forces that eventually give rise to stable planetary systems like our own.”

    The team is composed of L. Perez (Max Planck Institute for Radio Astronomy, Bonn, Germany), J. Carpenter (Joint ALMA Observatory, Santiago, Chile), S. Andrews (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.), L. Ricci (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.), A. Isella (Rice University, Houston, Texas), H. Linz (Max Planck Institute for Astronomy, Heidelberg, Germany), A. Sargent (Caltech, Pasadena, Calif.), D. Wilner (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.), T. Henning (Max Planck Institute for Astronomy, Heidelberg, Germany), A. Deller (The Netherlands Institute for Radio Astronomy, Dwingeloo), C. Chandler (National Radio Astronomy Observatory, Socorro, N.M.), C. Dullemond (Heidelberg University, Germany), J. Lazio (Caltech, Pasadena, Calif.), K. Menten (Max Planck Institute for Radio Astronomy, Bonn, Germany), S. Corder (Joint ALMA Observatory, Santiago, Chile), S. Storm (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.), L. Testi (European Southern Observatory, Garching, Germany), M. Tazzari (European Southern Observatory, Garching, Germany), W. Kwon (Korean Astronomy and Space Science Institute, Daejeon), N. Calvert (University of Michigan, Ann Arbor), J. Greaves (Cardiff University, U.K.), R. Harris (University of Illinois, Urbana), L. Mundy (University of Maryland, College Park).

    See the full article here .

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

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

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

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 1:22 pm on September 29, 2016 Permalink | Reply
    Tags: Astronomy, , , , , , Revealing the unseen Universe   

    From Nature: “Revealing the unseen Universe” 

    Nature Mag
    Nature

    28 September 2016
    Mark Zastrow

    Astronomy is entering an era in which gravitational waves and neutrinos will be used to complement existing techniques and to uncover the hidden features of our Universe.

    Gravitational waves

    When two black holes or neutron stars in a binary system spiral towards each other, their massive size causes ripples in space-time known as gravitational waves.

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib
    MPI for Gravitational Physics/W.Benger-Zib

    The strength of these waves increases as the black holes revolve faster, spiralling towards each other until they merge and there is a fall off in the signal (ringdown).

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project
    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    The Universe seems to be awash with these cataclysmic collisions, which astronomers expect to tell them how many black holes and neutron stars there are.

    2
    Illustration by Lucy Reading-Ikkanda

    How to detect gravitational waves

    In the Laser Interferometer Gravitational-Wave Observatory (LIGO), which detected gravitational waves for the first time in 2015, a laser beam is split in two, and each sent down a 4-kilometre tunnel.

    LIGO bloc new
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    “Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    The beams are reflected back and forth by mirrors at the end of each tunnel, before being recombined at a detector [1].

    3
    Illustration by Lucy Reading-Ikkanda

    Normal operations

    4
    Illustration by Lucy Reading-Ikkanda

    Effect of gravitational waves

    The waves warp the region of space-time that the tunnels sit in so that the beams seem to have travelled different distances when they merge. The difference is very small — about the width of an atomic nucleus for the first detection.

    5
    Illustration by Lucy Reading-Ikkanda

    Global network of detectors

    There are three operational gravitational wave detectors around the world: two LIGO arrays and Germany’s smaller GEO600 facility. Kamioka Gravitational Wave Detector (KAGRA) and Virgo are due to come online in 2018 and 2016, respectively, and a third LIGO detector in India is planned. Combining data from multiple detectors will allow scientists to locate the origin of the waves much more precisely. The laser arms of proposed space-based observatories, such as Europe’s eLISA and China’s Taiji and TianQin, would be much longer. They could detect gravitational waves at lower frequencies and reveal events from weaker sources than can be felt on Earth [2].

    6
    Illustration by Lucy Reading-Ikkanda

    High-energy neutrinos

    Particles known as neutrinos flood the Universe and are so small that they can zip straight through most matter, making them the ideal cosmic messenger. By studying neutrinos, scientists hope to piece together details of the events that made the particles.

    7
    llustration by Lucy Reading-Ikkanda

    IceCube neutrino observatory

    Located beneath the Amundsen–Scott South Pole Station, a US research facility, the detector of the IceCube neutrino observatory is arranged over one cubic kilometre of ice. IceCube’s sensitivity is partly due to the fact that ice in the region is one of the purest and most transparent solids on Earth [3].

    8
    Illustration by Lucy Reading-Ikkanda

    U Wisconsin ICECUBE neutrino detector at the South Pole
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector at the South Pole

    Timeline of high-energy neutrino discovery

    9
    Illustration by Lucy Reading-Ikkanda

    Sources
    1. LIGO Scientific Collaboration
    2. Nature 531, 150 (2016)
    3. IceCube/Univ. Wisconsin–Madison

    Related external links
    LIGO
    IceCube
    eLISA

    ESA/eLISA
    “ESA/eLISA

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 11:22 am on September 29, 2016 Permalink | Reply
    Tags: Analysing galaxy evolution in EAGLE, Angular momentum is a fundamental property of galaxies, Astronomy, ,   

    From CAASTRO: “EAGLE simulation shows gain & loss of galaxies’ angular momentum” 

    CAASTRO bloc

    CAASTRO ARC Centre of Excellence for All Sky Astrophysics

    29 September 2016
    No writer credit

    Angular momentum is a fundamental property of galaxies, together with mass and energy. It is crucial to many scaling relations, for example the relation between a galaxy’s luminosity and its rotational velocity and size. Galaxy formation theory postulates that the amount of angular momentum in spiral galaxies can be obtained by assuming that they formed in dark matter halos through conservation of angular momentum. Elliptical galaxies though, which have much lower spins, need to lose more than 90% of the angular momentum they were formed with. Galaxy mergers are the main scenario invoked to explain such a major loss.

    1

    In a new publication, CAASTRO member Dr Claudia Lagos (ICRAR-UWA) and colleagues analysed the evolution of the angular momentum of galaxies in the EAGLE hydrodynamical simulations. EAGLE is a state-of-the-art simulation that has a unique compromise between the resolution required to study the structural properties of galaxies (spatial resolution of 700 pc) and the simulated cosmological volume (100 Mpc box side length). This allows for the study of about 13,000 galaxies in the simulation-equivalent of the local Universe. EAGLE is unique in its accurate reconstruction of galaxy properties across multiple research studies, predicting galaxies of roughly the right sizes, morphologies, colours, gas contents and star formation throughout cosmic time.

    This new study has found a correlation between the galaxies’ specific angular momentum (i.e. angular momentum as function of mass) and their stellar mass – in excellent agreement with observations and with the positions of galaxies as they correlate with gas content.

    Analysing galaxy evolution in EAGLE paints a picture that is more complex than what theory predicted: galaxies that have high specific angular momentum now formed most of their stars during the second half of the age of the Universe, from gas that was falling into their halos with high specific angular momentum. In contrast, galaxies that have low specific angular momentum now formed most of their stars during the first half of the age of the Universe, from material that had much lower specific angular momentum compared to the infalling gas later. The researchers conclude that the simple picture of two alternative scenarios – conservation of specific angular momentum or mergers that spin-down galaxies – does not capture what EAGLE has revealed to happen. How quickly a galaxy spins appears to depend on the individual star formation history with a contribution from the merger history.

    Publication details:
    Claudia Lagos et al. in the Monthly Notices of the Royal Astronomical Society (2016): Angular momentum evolution of galaxies in EAGLE

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Astronomy is entering a golden age, in which we seek to understand the complete evolution of the Universe and its constituents. But the key unsolved questions in astronomy demand entirely new approaches that require enormous data sets covering the entire sky.

    In the last few years, Australia has invested more than $400 million both in innovative wide-field telescopes and in the powerful computers needed to process the resulting torrents of data. Using these new tools, Australia now has the chance to establish itself at the vanguard of the upcoming information revolution centred on all-sky astrophysics.

    CAASTRO is a collaboration of The University of Sydney, The Australian National University, The University of Melbourne, Swinburne University of Technology, The University of Queensland, The University of Western Australia and Curtin University, the latter two participating together as the International Centre for Radio Astronomy Research (ICRAR). CAASTRO is funded under the Australian Research Council (ARC) Centre of Excellence program, with additional funding from the seven participating universities and from the NSW State Government’s Science Leveraging Fund.

     
  • richardmitnick 10:46 am on September 29, 2016 Permalink | Reply
    Tags: Astronomy, , , , New Castle Herald,   

    From CSIRO via New Castle Herald: Women in STEM: “University of Newcastle graduate Karlie Noon thanks Wollotuka Institute” 

    CSIRO bloc

    Commonwealth Scientific and Industrial Research Organisation

    1

    New Castle Herald

    26 Sep 2016
    Helen Gregory

    1
    Karlie wants to inspire the next generation of young innovators.

    KARLIE Noon will become the first indigenous person in the state to attain a double degree in science and mathematics when she pulls on her academic gown for her University of Newcastle (UON) graduation this week.

    Ms Noon, a 26-year-old Kamilaroi woman from Tamworth, will be one of more than 1000 students who will graduate at ceremonies at the Callaghan campus on Thursday and Friday.

    “It’s hard to describe the impact finishing university has had back home,” Ms Noon said.

    “It has helped shift perceptions and raised the expectations for the people around me. My sister has since enrolled in a Bachelor of Nursing at UON after entering through the indigenous enabling program Yapug – and my cousin is also talking to me about going to university and studying science.”

    UON reached a milestone 1000 indigenous enrolments this year, which is equivalent to 3.5 per cent of its student population and the largest number at any Australian university.

    Ms Noon missed most of primary school but an indigenous elder tutored her once a week in maths.

    She enrolled in a Bachelor of Arts, but became interested in physics and changed degrees. “It was really challenging coming into a first year maths degree with no background but I was so determined to do it,” she said. “The Wollotuka Institute really were my support network here for anything I needed.”

    Ms Noon now works for the CSIRO, but her love of learning is far from over.

    A chance meeting with Monash University cultural astronomer, Dr Duane Hamacher, has encouraged her to pursue postgraduate study in indigenous astronomy.

    “I had experienced indigenous astronomy from a cultural perspective, but studying it in a Western paradigm wasn’t something I knew existed,” she said. “There are a lot of similarities between indigenous knowledge and physics, which I plan to explore further.”

    Ms Noon has also set her sights on obtaining her PhD. “It is the epitome of academia and at the moment there are no indigenous people with a PhD in Physics.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
  • richardmitnick 9:17 am on September 29, 2016 Permalink | Reply
    Tags: Astronomy, , , Orion Spur, Where is the Milky Way?   

    From New Scientist: “Our home spiral arm in the Milky Way is less wimpy than thought” 

    NewScientist

    New Scientist

    28 September 2016

    It’s tricky to map an entire galaxy when you live in one of its arms. But astronomers have made the clearest map yet of the Milky Way – and it turns out that the arm that hosts our solar system is even bigger than previously thought.

    The idea that the Milky Way is a spiral was first proposed more than 150 years ago, but we only started identifying its limbs in the 1950s. Details about the galaxy’s exact structure are still hotly debated, such as the number of arms, their length and the size of the bar of hot gas and dust that stretches across its middle.

    The star-filled arms are densely packed with gas and dust, where new stars are born. That dust can obscure stars we use to measure distances, complicating the mapping process.

    .
    Two of the arms, called Perseus and Scutum-Centaurus, are larger and filled with more stars, while the Sagittarius and Outer arms have fewer stars but just as much gas. The solar system has been thought to lie in a structure called the Orion Spur, or Local Arm, which is smaller than the nearby Perseus Arm.

    1
    Artist’s conception of the Milky Way galaxy as seen from far Galactic North (in Coma Berenices) by NASA/JPL-Caltech/R. Hurt annotated with arms (colour-coded according to Milky Way article) as well as distances from the Solar System and galactic longitude with corresponding constellation.

    Just as grand

    Now, Ye Xu and colleagues from the Purple Mountain Observatory in Nanjing, China, say the Local Arm is just as grand as the others.

    Purple Mountain Observatory
    Purple Mountain Observatory in Nanjing, China

    The team used the Very Long Baseline Array in New Mexico to make extremely accurate measurements of high-mass gas clouds in the arms, and used a star-measuring trigonometry trick called parallax to measure their distances.

    NRAO VLBA
    NRAO VLBA

    “Radio telescopes can ‘see’ through the galactic plane to massive star forming regions that trace spiral structure, while optical wavelengths will be hidden by dust,” Xe says. “Achieving a highly accurate parallax is not easy.”

    The new measurements suggest the Milky Way is not a grand design spiral with well-defined arms, but a spiral with many branches and subtle spurs.

    However, Xu and colleagues say the Orion Spur is not a spur at all, but more in line with the galaxy’s other spectacular arms. The team also discovered a spur connecting the Local and Sagittarius arms.

    “This lane has received little attention in the past because it does not correspond with any of the major spiral arm features of the inner galaxy,” the authors of the study write.

    Future measurements with other radio telescopes will shed more light on the galaxy’s shape. The European Space Agency’s Gaia spacecraft is in the midst of a mission to make a three-dimensional map of our galaxy, too.

    ESA/GAIA satellite
    ESA/GAIA satellite

    More measurements of the high-mass gas regions will help astronomers determine what our galaxy looks like, from the inside out.

    Journal reference: Science Advances, DOI: 10.1126/sciadv.1600878

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 7:31 am on September 29, 2016 Permalink | Reply
    Tags: , ALMA Catches Stellar Cocoon with Curious Chemistry, Astronomy, , ,   

    From ALMA: “ALMA Catches Stellar Cocoon with Curious Chemistry” 

    ALMA Array

    ALMA

    29 September 2016
    Contacts

    Takashi Shimonishi
    Frontier Research Institute for Interdisciplinary Sciences
    Tohoku University, Sendai, Miyagi, Japan
    Email: shimonishi@astr.tohoku.ac.jp

    Masaaki Hiramatsu
    NAOJ Chile Observatory EPO officer
    Tel: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

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

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

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

    1

    A hot and dense mass of complex molecules, cocooning a newborn star, has been discovered by a Japanese team of astronomers using ALMA. This unique hot molecular core is the first of its kind to have been detected outside the Milky Way galaxy. It has a very different molecular composition from similar objects in our own galaxy — a tantalising hint that the chemistry taking place across the Universe could be much more diverse than expected.

    A team of Japanese researchers have used the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a massive star known as ST11 [1] in our neighbouring dwarf galaxy, the Large Magellanic Cloud (LMC). Emission from a number of molecular gases was detected. These indicated that the team had discovered a concentrated region of comparatively hot and dense molecular gas around the newly ignited star ST11. This was evidence that they had found something never before seen outside of the Milky Way — a hot molecular core [2].

    Takashi Shimonishi, an astronomer at Tohoku University, Japan, and the paper’s lead author enthused: “This is the first detection of an extragalactic hot molecular core, and it demonstrates the great capability of new generation telescopes to study astrochemical phenomena beyond the Milky Way.”

    The ALMA observations revealed that this newly discovered core in the LMC has a very different composition to similar objects found in the Milky Way. The most prominent chemical signatures in the LMC core include familiar molecules such as sulfur dioxide, nitric oxide, and formaldehyde — alongside the ubiquitous dust. But several organic compounds, including methanol (the simplest alcohol molecule), had remarkably low abundance in the newly detected hot molecular core. In contrast, cores in the Milky Way have been observed to contain a wide assortment of complex organic molecules, including methanol and ethanol.

    Takashi Shimonishi explains: “The observations suggest that the molecular compositions of materials that form stars and planets are much more diverse than we expected.”

    4
    Fig.2 Left: Distributions of molecular line emission from a hot molecular core in the Large Magellanic Cloud observed with ALMA. Emissions from dust, sulfur dioxide (SO2), nitric oxide (NO), and formaldehyde (H2CO) are shown as examples. Right: An infrared image of the surrounding star-forming region (based on the 8 micron data provided by the NASA/Spitzer Space Telescope). Credit: T. Shimonishi/Tohoku University, ALMA (ESO/NAOJ/NRAO)

    The LMC has a low abundance of elements other than hydrogen or helium [3]. The research team suggests that this very different galactic environment has affected the molecule-forming processes taking place surrounding the newborn star ST11. This could account for the observed differences in chemical compositions.

    It is not yet clear if the large, complex molecules detected in the Milky Way exist in hot molecular cores in other galaxies. Complex organic molecules are of very special interest because some are connected to prebiotic molecules formed in space. This newly discovered object in one of our nearest galactic neighbours is an excellent target to help astronomers address this issue. It also raises another question: how could the chemical diversity of galaxies affect the development of extragalactic life?

    Notes

    [1] ST11’s full name is 2MASS J05264658-6848469. This catchily-named young massive star is defined as a Young Stellar Object. Although it currently appears to be a single star, it is possible that it will prove to be a tight cluster of stars, or possibly a multiple star system. It was the target of the science team’s observations and their results led them to realise that ST11 is enveloped by a hot molecular core.

    [2] Hot molecular cores must be: (relatively) small, with a diameter of less than 0.3 light-years; have a density over a thousand billion (1012) molecules per cubic metre (far lower than the Earth’s atmosphere, but high for an interstellar environment); warm in temperature, at over –173 degrees Celsius. This makes them at least 80 degrees Celsius warmer than a standard molecular cloud, despite being of similar density. These hot cores form early on in the evolution of massive stars and they play a key role in the formation of complex chemicals in space.

    [3] The nuclear fusion reactions that take place when a star has stopped fusing hydrogen to helium generate heavier elements. These heavier elements get blasted into space when massive dying stars explode as supernovae. Therefore, as our Universe has aged, the abundance of heavier elements has increased. Thanks to its low abundance of heavier elements, the LMC provides insight into the chemical processes that were taking place in the earlier Universe.

    More information

    This research was presented in a paper published in the Astrophysical Journal on August 9, 2016, entitled The Detection of a Hot Molecular Core in the Large Magellanic Cloud with ALMA.

    The team is composed of Takashi Shimonishi (Frontier Research Institute for Interdisciplinary Sciences & Astronomical Institute, Tohoku University, Japan), Takashi Onaka (Department of Astronomy, The University of Tokyo, Japan), Akiko Kawamura (National Astronomical Observatory of Japan, Japan) and Yuri Aikawa (Center for Computational Sciences, The University of Tsukuba, Japan).

    See the full article here .

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

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

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

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 3:54 pm on September 28, 2016 Permalink | Reply
    Tags: Astronomy, , ,   

    From UCLA: “Research resolves a debate over ‘killer electrons’ in space” 

    UCLA bloc

    UCLA

    September 28, 2016
    Stuart Wolpert

    1
    A visualization of the Earth’s magnetic environment. Martin Rother/GFZ Research Centre for Geosciences.

    New findings by a UCLA-led international team of researchers answer a fundamental question about our space environment and will help scientists develop methods to protect valuable telecommunication and navigation satellites. The research is published today in the journal Nature Communications.

    Using measurements from the first U.S. satellite that traveled to space, Explorer 1 physicist James Van Allen discovered in 1958 that space is radioactive. The Earth is surrounded by two doughnut-shaped rings of highly charged particle radiation — an inner ring of high-energy electrons and positive ions and an outer ring of high-energy electrons — that are now known as Van Allen Radiation Belts. Flying close to the speed of light, the high-energy particles that populate the belts create a harsh environment for satellites and humans in space.

    In recent years, there has been much scientific interest in understanding the Van Allen belts. New technologies now require that telecommunication satellites spend a great deal of time in those belts and that GPS satellites operate in the heart of the belts. With the increasingly smaller size of space electronics has come greater vulnerability of satellites to space radiation, according to Yuri Shprits, a research geophysicist with Earth, Planetary and Space Sciences in the UCLA College and a member of the international team.

    The particles that are most dangerous to spacecraft are known as relativistic and ultra-relativistic electrons. The ultra-relativistic, or “killer electrons,” are especially hazardous and can penetrate the most protected and valuable satellites in space, Shprits said. While it is possible to protect the satellites from relativistic particles, shielding from ultra-relativistic particles is practically impossible, he added.

    Understanding the dynamics of these particles has been a major challenge for scientists since Van Allen discovered space radiation. Since the late 1960s, scientists have made many observations to try to understand the loss of electrons from the Van Allen belts.

    One of the proposed theories was that particles are scattered into the atmosphere by electromagnetic ion cyclotron waves. These waves are produced by the injection of ions that are heavier than electrons and carry a lot of energy. These waves can potentially scatter electrons into the atmosphere. Up until recently, that remained the most likely candidate for the loss of electrons.

    In 2006, Shprits and colleagues proposed another mechanism. They suggested that more than 99 percent of the particles suddenly were lost, as electrons diffused into interplanetary space, no longer trapped by the Earth’s magnetic field. The team conducted additional studies that provided more evidence for this mechanism.

    The scientists’ modeling of large numbers of electrons at relativistic energies seemed to favor this mechanism and did not require the scattering of electron by electromagnetic ion cyclotron waves. However, it remained unclear which mechanism operated or dominated during storms, and which mechanism explains the most dramatic dropouts of electrons in the space environment.

    The loss of particles is difficult to pinpoint. Both types of loss mechanisms are intensified during storms, making it difficult to distinguish one from the other.

    2
    An illustration of the structure of the Van Allen Radiation Belt after a storm. Copyright Ingo Michaelis. Background image courtesy of European Space Agency/NAS.

    Fortunately for the scientists, several factors combined to help them resolve the dispute. A January 2013 storm in the Van Allen belts allowed the researchers to use detectors to measure the particles’ distributions and direction. The most intense relativistic and ultra-relativistic electrons were discovered in different locations in the belts. And the ultra-relativistic particles were located deep inside the magnetosphere (and were not affected by the electron loss to the magnetopause, which is the boundary between the Earth’s magnetic field and the solar wind).

    The researchers’ detailed measurements — including particle speed, velocity direction and radial distributions — all showed that the waves were indeed scattering particles into the atmosphere but affected only ultra-relativistic electrons, not relativistic particles.

    “Our findings resolve a fundamental scientific question about our space environment and may help develop methods of cleaning up the radiation belts from harmful radiation and make the environment around the Earth friendlier for satellites,” Shprits said. He is principal investigator of an April mission in which a satellite containing a UCLA-built collection of instruments was launched from Vostochny, Siberia. That work is expected to provide scientists worldwide with measurements of radiation in space and advance space sciences for years to come.

    Other members of the team are scientists from UCLA (researchers Alexander Drozdov and Adam Kellerman, and postdoctoral scholar Hui Zhu); Germany’s GFZ Research Centre for Geosciences in Potsdam (Irina Zhelavskaya and Nikita Aseev, who were visiting scholars at UCLA for six months in 2015-16; Shprits holds a joint appointment here); Stanford University (Maria Spasojevic); University of Colorado, Boulder (Maria Usanova and Daniel Baker); Augsburg College in Minneapolis (Mark Engebretson); UC Berkeley (Oleksiy Agapitov, who also has an appointment at Ukraine’s University of Kyiv); Finland’s University of Oulu (Tero Raita); and the University of New Hampshire (Harlan Spence).

    Funding sources for the Nature Communications research included the University of California Office of the President, National Science Foundation, NASA and the Helmholtz Association Recruiting Imitative program.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 3:41 pm on September 28, 2016 Permalink | Reply
    Tags: Astronomy, , ,   

    From Frontier Fields: “Beyond the Frontier Fields: How JWST Will Push the Science to a New Frontier” 

    Frontier Fields
    Frontier Fields

    September 28, 2016
    bonniemeinke

    The Frontier Fields Project has been an ambitious campaign to see deep into our universe. Gravitational lensing, as used by the Frontier Fields Project, enables Hubble to see fainter and more-distant galaxies than would otherwise be possible. These images push to the very limits of how deeply Hubble can see out into space.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    Hubble, Spitzer, Chandra, and other observatories are doing cutting-edge science through the Frontier Fields Project, but there’s a challenge.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    Even though leveraging gravitational lensing has allowed astronomers to see objects that otherwise could not be detected with today’s telescopes, the technique still isn’t enough to see the most distant galaxies. As the universe expands, light gets stretched into longer and longer wavelengths, beyond the visible and near-infrared wavelengths Hubble can detect. To see the most distant galaxies, one needs a space telescope with Hubble’s keen resolution, but at infrared wavelengths.

    That infrared telescope is the James Webb Space Telescope, slated to launch in October 2018. It has a mirror 6.5 meters (21 feet) across, can observe wavelengths up to 10 times longer than Hubble can observe, and is the mission that will detect and study the first appearances of galaxies in the universe.

    1
    Figure 1: Webb will have a 6.5-meter-diameter primary mirror, which would give it a significant larger collecting area than the mirrors available on the current generation of space telescopes. Hubble’s mirror is a much smaller 2.4 meters in diameter, and its corresponding collecting area is 4.5 square meters, giving Webb around seven times more collecting area! Webb’s field of view is more than 15 times larger than the NICMOS near-infrared camera on Hubble. It also will have significantly better spatial resolution than is available with the infrared Spitzer Space Telescope. Credit: NASA. http://webbtelescope.org/gallery.

    Observations of the early universe are still incomplete. To build the full cosmological history of our universe, we need to see how the first stars and galaxies formed, and how those galaxies evolved into the grand structures we see today.

    Looking back in time to the first light in the universe:

    Astronomers use light to explore the universe, but there are pieces of our universe’s early history where there wasn’t much light. The era of the universe called the “Dark Ages” is as mysterious as its name implies. Shortly after the Big Bang, our universe was filled with glowing plasma, or ionized gas. As the universe cooled and expanded, electrons and protons began to bind together to form neutral hydrogen atoms (one proton and one electron each). The last of the light from the Big Bang escaped (becoming what we now detect as the Cosmic Microwave Background [CMB]).

    CMB per ESA/Planck
    CMB per ESA/Planck

    The universe would have been a dark place, with no sources of light to reveal this cooling, neutral hydrogen gas.

    Some of that gas would have begun coalescing into dense clumps, pulled together by gravity. As these clumps grew larger, they would become stars and eventually galaxies. Slowly, starlight would begin to shine in the universe. Eventually, as the early stars grew in numbers and brightness, they would have emitted enough ultraviolet light to “reionize” the universe by stripping electrons off neutral hydrogen atoms, leaving behind individual protons. This process created a hot plasma of free electrons and protons. At this point, the light from star and galaxy formation could travel freely across space and illuminate the universe. It is important to note here, astronomers are currently unsure whether the energy responsible for reionization came from stars in the early-forming galaxies; rather, it might have come from hot gas surrounding massive black holes or some even more exotic source such as decaying dark matter.

    The universe’s first stars, believed to be 30 to 300 times as massive as our Sun and millions of times as bright, would have burned for only a few million years before dying in tremendous explosions, or “supernovae.” These explosions spewed the recently manufactured chemical elements of stars outward into the universe before the expiring stars collapsed into black holes.

    Astronomers know the universe became reionized because when they look back at quasars — incredibly bright objects thought to be powered by supermassive black holes — in the distant universe, they don’t see the dimming of their light that would occur if the light passed through a fog of neutral hydrogen gas. While they find clouds of neutral hydrogen gas, they see almost no signs of neutral hydrogen gas in the matter located in the space between galaxies. This means that at some point the matter was reionized. Exactly when this occurred is one of the questions Webb will help answer, by looking for glimpses of very distant objects still dimmed by neutral hydrogen gas.

    Much remains to be uncovered about the time of reionization. The universe right after the Big Bang would have consisted of hydrogen, helium, and a small amount of lithium. But the stars we see today also contain heavier elements — elements that are created inside stars. So how did those first stars form from such limited ingredients? Webb may not be able to see the very first stars of the Dark Ages, but it’ll witness the generation of stars immediately following, and analyze the kinds of materials they contain.

    Webb’s ability to see the infrared light from the most distant objects in the universe will allow it to truly identify the sources that gave rise to reionization. For the first time, we will be able to see the stars and quasars that unleashed enough energy to illuminate the universe again.

    2
    Figure 2: JWST will be able to see back to when the first bright objects (stars and galaxies) were forming in the early universe. Credit: STScI. http://jwst.nasa.gov/firstlight.html

    Early Galaxies:

    Webb will also show us how early galaxies formed from those first clumps of stars. Scientists suspect the black holes born from the explosions of the earliest stars (supernovae) devoured gas and stars around them, becoming the extremely bright objects called “mini-quasars.” The mini-quasars, in turn, may have grown and merged to become the huge black holes found in the centers of present-day galaxies. Webb will try to find and understand these supernovae and mini-quasars to put theories of early galaxy formation to the test. Do all early galaxies have these mini-quasars or only some? These regions give off infrared light as the gas around them cools, allowing Webb to glean information about how mini-quasars in the early universe work — how hot they are, for instance, and how dense.

    Webb will show us whether the first galaxies formed along lines and webs of dark matter, as expected, and when. Right now we know the first galaxies formed anywhere from 378,000 years to 1 billion years after the Big Bang. Many models have been created to explain which era gave rise to galaxies, but Webb will pinpoint the precise time period.

    Hubble is known for its deep-field images, which capture slices of the universe throughout time. But these images stop at the point beyond which Hubble’s vision cannot reach. Webb will fill in the gaps in these images, extending them back to the Dark Ages. Working together, Hubble and Webb will help us visualize much more of the universe than we ever have before, creating for us an unprecedented picture that stretches from the current day to the beginning of the recognizable universe.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated
    http://webbtelescope.org/gallery

    Resources:

    https://frontierfields.org/2016/07/21/the-final-frontier-of-the-universe/

    http://hubble25th.org/science/8

    http://webbtelescope.org/article/13

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Frontier Fields draws on the power of massive clusters of galaxies to unleash the full potential of the Hubble Space Telescope. The gravity of these clusters warps and magnifies the faint light of the distant galaxies behind them. Hubble captures the boosted light, revealing the farthest galaxies humanity has ever encountered, and giving us a glimpse of the cosmos to be unveiled by the James Webb Space Telescope.

    NASA Hubble Telescope
    Hubble
    NASA James Webb Telescope
    Webb

     
  • richardmitnick 3:16 pm on September 28, 2016 Permalink | Reply
    Tags: Astronomy, , , Modular Space Telescope Could Be Assembled By Robot,   

    From Caltech: “Modular Space Telescope Could Be Assembled By Robot” 

    Caltech Logo
    Caltech

    09/28/2016
    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    1
    Illustration shows how a robot could assemble the trusses that would support a massive telescope mirror. Credit: Sergio Pellegrino/Caltech

    2
    Figure shows how foldable truss modules can be combined and assembled to support stackable mirror modules, ultimately creating a single large mirror.
    Credit: Sergio Pellegrino/Caltech

    Seeing deep into space requires large telescopes. The larger the telescope, the more light it collects, and the sharper the image it provides.

    For example, NASA’s Kepler space observatory, with a mirror diameter of under one meter, is searching for exoplanets orbiting stars up to 3,000 light-years away. By contrast, the Hubble Space Telescope, with a 2.4-meter mirror, has studied stars more than 10 billion light-years away.

    Now Caltech’s Sergio Pellegrino and colleagues are proposing a space observatory that would have a primary mirror with a diameter of 100 meters—40 times larger than Hubble’s. Space telescopes, which provide some of the clearest images of the universe, are typically limited in size due to the difficulty and expense of sending large items into space. Pellegrino’s team would circumvent that issue by shipping the mirror up as separate components that would be assembled, in space, by robots.

    Their design calls for the use of more than 300 deployable truss modules that could be unfolded to form a scaffolding upon which a commensurate number of small mirror plates could be placed to create a large segmented mirror. The assembly of the scaffolding and the attachment of the many mirrors is a task well-suited to robots, Pellegrino and his colleagues say.

    In their concept, a spider-like, six-armed “hexbot” would assemble the trusswork and then crawl across the structure to build the mirror atop it. It was modeled on the JPL RoboSimian system, which in 2015 completed the DARPA Robotics Challenge, a federal competition aimed at spurring the development of robots that could perform complicated tasks that would be dangerous for humans. The hexbot would run on electrical power from the telescope’s solar grid. It would use four of its arms to walk—with one leg moving at any given time, while the three others remain securely attached to the structure. The two remaining arms would be free to assemble the trusses and mirrors.

    The team opted to pursue an ambitious 100-meter design. “We wanted to study how different kinds of architectures perform as the diameter is increased,” says Pellegrino, Joyce and Kent Kresa Professor of Aeronautics and Professor of Civil Engineering in Caltech’s Division of Engineering and Applied Science, and Jet Propulsion Laboratory Senior Research Scientist. “We found that far away from the Earth, a structurally connected telescope is much heavier than an architecture based on separate spacecraft for the primary mirror, the optics, and the instrumentation.”

    The realization of such an assembly is still decades away. However, Pellegrino and his colleagues are already working on the various technologies that will be needed to make it possible.

    The entire space observatory would be composed of the fully assembled mirror-and-truss structure and three other parts, flying in formation. An optics and instrumentation unit would be located about 400 meters from the mirror; a control unit, stationed about 400 meters beyond that, would align the system and keep it working properly; and a thin shade, roughly 20 meters in diameter, would shield the mirror from the sun to keep its temperature stable and consistent across its diameter.

    The four-part assembly would be stationed at one of the sun–earth Lagrange points—locations between the sun and the earth where the pull of gravity from two bodies locks a satellite into orbit with them, allowing it to maintain a stable position. There, the space observatory could peer deep into space without drifting out of place.

    Pellegrino collaborated with Joel Burdick, Nicolas Lee, and Kristina Hogstrom of Caltech, as well as Paul Backes, Christine Fuller, Brett Kennedy, Junggon Kim, Rudranarayan Mukherjee, Carl Seubert, and Yen-Hung Wu of JPL. A paper about the work, titled “Architecture for in-space robotic assembly of a modular space telescope,” was published by the Journal of Astronomical Telescopes, Instruments, and Systems. This research was supported by NASA and the W. M. Keck Institute for Space Studies.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    Caltech campus
    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: