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  • richardmitnick 12:08 pm on March 27, 2018 Permalink | Reply
    Tags: , , , , , , , , National Computational Infrastructure at the Australian National University in Canberra, SkyMapper telescope at Siding Spring Observatory, SN KSN 2015K, Supernova   

    From Space Science Telescope Institute via COSMOS: “Gone in a flash: supernova burns up in just 25 days” 

    Space Science Telescope Institute

    COSMOS

    27 March 2018
    Lauren Fuge

    Huge, bright and incredibly violent, a new supernova provides new challenges for astronomers.

    1
    An artists impression of how the explosive light of the supernova was hidden for a while behind a cocoon of ejected dust. Nature Astronomy.

    Astronomers have witnessed a blazing supernova explosion that faded away 10 times faster than expected.

    A supernova is the violent death of a massive star, typically occurring when it exhausts its fuel supply and collapses under its own weight, generating a powerful shockwave that blasts light and material out into space.

    Supernovae often blaze so brightly that they briefly outshine all the other stars in their host galaxy. They show off for months on end — in 1054, a supernova could be seen during the day for three weeks and only disappeared completely after two years. Its remnants are known as the Crab Nebula.

    2
    The Crab Nebula in all its glory. NASA, ESA, NRAO/AUI/NSF and G. Dubner (University of Buenos Aires).

    Now an international team of astronomers, led by Armin Rest from the Space Science Telescope Institute in Baltimore, US, has observed a supernova that rapidly soared to its peak brightness in 2.2 days then faded away in just 25.

    “When I first saw the Kepler data, and realised how short this transient is, my jaw dropped,” recalls Rest.

    The supernova, dubbed KSN 2015K, is part of a puzzling class of rare events called Fast-Evolving Luminous Transients (FELTs).

    4
    KSN 2015K’s host is the star-forming spiral galaxy 2MASX-J13315109-1044061. Image credit: Rest et al: https://www.nature.com/articles/s41550-018-0423-2.

    FELTs don’t fit into existing supernova models and astronomers are still debating their sources. Previous suggestions include the afterglow of a gamma-ray burst, a supernova turbo-boosted by a magnetically-powerful neutron star, or a failed example of special type of binary star supernova known as a type 1a. KSN 2015K is the most extreme example found so far.

    In a paper published in the journal Nature Astronomy, the team says that KSN 2015K’s behaviour can most likely be explained by its surroundings: the star was swathed in dense gas and dust that it ejected in its old age, like a caterpillar spinning a cocoon. When the supernova detonated, it took some time for the resulting shock wave to slam into the shell of material and produce a burst of light, becoming visible to astronomers.

    KSN 2015K was captured by NASA’s Kepler Space Telescope, which is designed to hunt for planets by noticing the tiny, temporary dips in light from far-away stars when planets pass in front of them.

    NASA/Kepler Telescope

    Planet transit. NASA/Ames

    This exact skill is also useful in studying supernovae and other brief, explosive events.

    “Using Kepler’s high-speed light-measuring capabilities, we’ve been able to see this exotic star explosion in incredible detail,” says team member Brad Tucker, an astrophysicist from the Australian National University.

    Co-author David Khatami from the University of California, Berkeley, US, adds that this is the first time astronomers can test FELT models to a high degree of accuracy. “The fact that Kepler completely captured the rapid evolution really constrains the exotic ways in which stars die,” he says.

    Australian researchers and facilities were also key to this discovery. Follow-up observations were made with the SkyMapper telescope at Siding Spring Observatory, and then processed by the National Computational Infrastructure at the Australian National University in Canberra.

    ANU Skymapper telescope, a fully automated 1.35 m (4.4 ft) wide-angle optical telescope, at Siding Spring Observatory , near Coonabarabran, New South Wales, Australia, Altitude 1,165 m (3,822 ft)

    Siding Spring Observatory, near Coonabarabran, New South Wales, Australia, Altitude 1,165 m (3,822 ft)

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    The National Computational Infrastructure building at the Australian National University

    Tucker says that by learning more about how stars live and die, astronomers can better understand solar systems as a whole, including the potential life on orbiting planets.

    He concludes: “With the imminent launch of NASA’s new space telescope, TESS, we hope to find even more of these rare and violent explosions.”

    NASA/TESS

    See the full article here . Other articles here and here and here.

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    Founded in 1982, we have helped guide the most famous observatory in history, the Hubble Space Telescope.

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    Since its launch in 1990, we have performed the science operations for Hubble. We also lead the science and mission operations for the James Webb Space Telescope (JWST), scheduled for launch in 2019.

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  • richardmitnick 10:34 am on August 18, 2017 Permalink | Reply
    Tags: A Fleeting Blue Glow, , , , , LCO-Las Cumbres Observatory, Supernova,   

    From UCSB: “A Fleeting Blue Glow” 

    UC Santa Barbara Name bloc
    UC Santa Barbara

    August 14, 2017
    Julie Cohen

    Observations of a supernova colliding with a nearby companion star take UCSB astrophysicists by surprise.

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    Only 55 million lightyears away, this is one of the closest supernovae discovered in recent years.

    In the 2009 film “Star Trek,” a supernova hurtles through space and obliterates a planet unfortunate enough to be in its path. Fiction, of course, but it turns out the notion is not so farfetched.

    Using the nearby Las Cumbres Observatory (LCO), astrophysicists from UC Santa Barbara have observed something similar: an exploding star slamming into a nearby companion star.

    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA

    What’s more, they detected the fleeting blue glow from the interaction at an unprecedented level of detail. Their observations revealed surprising information about the mysterious companion star, a feat made possible by recent advances in linking telescopes into a robotic network. The team’s findings appear in the journal Astrophyiscal Journal Letters.

    The identity of this particular companion has been hotly debated for more than 50 years. Prevailing theory over the last few years has held that the supernovae happen when two white dwarfs spiral together and merge. This new study demonstrates that the supernova collided with the companion star that was not a white dwarf. White dwarf stars are the dead cores of what used to be normal stars like the sun.

    “We’ve been looking for this effect — a supernova crashing into its companion star — since it was predicted in 2010,” said lead author Griffin Hosseinzadeh, a UCSB graduate student. “Hints have been seen before, but this time the evidence is overwhelming.”

    The supernova in question is SN 2017cbv, a thermonuclear Type Ia, which astronomers use to measure the acceleration of the expansion of the universe. This kind of supernova is known to be the explosion of a white dwarf star, though it requires additional mass from a companion star to explode.

    The UCSB-led research implies that the white dwarf was stealing matter from a much larger companion star — approximately 20 times the radius of the sun — which caused the white dwarf to explode. The collision of the supernova and the companion star shocked the supernova material, heating it to a blue glow heavy in ultraviolet light. Such a shock could not have been produced if the companion were another white dwarf star.

    “The universe is crazier than science fiction authors have dared to imagine,” said Andy Howell, a staff scientist at LCO and Hosseinzadeh’s Ph.D. adviser. “Supernovae can wreck nearby stars, too, releasing unbelievable amounts of energy in the process.”

    Co-author David Sand, an associate professor at the University of Arizona, discovered the supernova on March 10, 2017, in the galaxy NGC 5643. Only 55 million lightyears away, SN 2017cbv was one of the closest supernovae discovered in recent years, found by the DLT40 survey using the Panchromatic Robotic Optical Monitoring and Polarimetry Telescope (PROMPT) in Chile, which monitors galaxies nightly at distances less than 40 megaparsecs (120 million light-years). This was one of the earliest catches ever — within a day, perhaps even hours, of its explosion. The DLT40 survey was created by Sand and study co-author Stefano Valenti, an assistant professor at UC Davis; both were previously postdoctoral researchers at LCO.

    Within minutes of discovery, Sand activated observations with LCO’s global network of 18 robotic telescopes, spaced around the Earth so that one is always on the night side. This allowed the team to take immediate and near-continuous observations.

    “With LCO’s ability to monitor the supernova every few hours, we were able to see the full extent of the rise and fall of the blue glow for the first time,” Hosseinzadeh said. “Conventional telescopes would have had only a data point or two and missed it.”

    Howell likened the event to gaining astronomical superpowers that give astronomers the ability to see the universe in new ways. “These capabilities were just a dream a few years ago,” he said. “But now we’re living the dream and unlocking the origins of supernovae in the process.”

    See the full article here .

    Please help promote STEM in your local schools.

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    UC Santa Barbara Seal
    The University of California, Santa Barbara (commonly referred to as UC Santa Barbara or UCSB) is a public research university and one of the 10 general campuses of the University of California system. Founded in 1891 as an independent teachers’ college, UCSB joined the University of California system in 1944 and is the third-oldest general-education campus in the system. The university is a comprehensive doctoral university and is organized into five colleges offering 87 undergraduate degrees and 55 graduate degrees. In 2012, UCSB was ranked 41st among “National Universities” and 10th among public universities by U.S. News & World Report. UCSB houses twelve national research centers, including the renowned Kavli Institute for Theoretical Physics.

     
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