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News Article | May 11, 2017
Site: spaceref.com

Astronomers have produced a highly detailed image of the Crab Nebula They did so by combining data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum, from radio waves seen by the Karl G. Jansky Very Large Array (VLA) to the powerful X-ray glow as seen by the orbiting Chandra X-ray Observatory. And, in between that range of wavelengths, the Hubble Space Telescope's crisp visible-light view, and the infrared perspective of the Spitzer Space Telescope. The Crab Nebula, the result of a bright supernova explosion seen by Chinese and other astronomers in the year 1054, is 6,500 light-years from Earth. At its center is a super-dense neutron star, rotating once every 33 milliseconds, shooting out rotating lighthouse-like beams of radio waves and light -- a pulsar (the bright dot at image center). The nebula's intricate shape is caused by a complex interplay of the pulsar, a fast-moving wind of particles coming from the pulsar, and material originally ejected by the supernova explosion and by the star itself before the explosion. This image combines data from five different telescopes: the VLA (radio) in red; Spitzer Space Telescope (infrared) in yellow; Hubble Space Telescope (visible) in green; XMM-Newton (ultraviolet) in blue; and Chandra X-ray Observatory (X-ray) in purple. The new VLA, Hubble, and Chandra observations all were made at nearly the same time in November of 2012. A team of scientists led by Gloria Dubner of the Institute of Astronomy and Physics (IAFE), the National Council of Scientific Research (CONICET), and the University of Buenos Aires in Argentina then made a thorough analysis of the newly revealed details in a quest to gain new insights into the complex physics of the object. They are reporting their findings in the Astrophysical Journal. "Comparing these new images, made at different wavelengths, is providing us with a wealth of new detail about the Crab Nebula. Though the Crab has been studied extensively for years, we still have much to learn about it," Dubner said. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | May 25, 2017
Site: www.eurekalert.org

Astronomers have watched as a massive, dying star was likely reborn as a black hole. It took the combined power of the Large Binocular Telescope (LBT), and NASA's Hubble and Spitzer space telescopes to go looking for remnants of the vanquished star, only to find that it disappeared out of sight. It went out with a whimper instead of a bang. The star, which was 25 times as massive as our sun, should have exploded in a very bright supernova. Instead, it fizzled out--and then left behind a black hole. "Massive fails" like this one in a nearby galaxy could explain why astronomers rarely see supernovae from the most massive stars, said Christopher Kochanek, professor of astronomy at The Ohio State University and the Ohio Eminent Scholar in Observational Cosmology. As many as 30 percent of such stars, it seems, may quietly collapse into black holes -- no supernova required. "The typical view is that a star can form a black hole only after it goes supernova," Kochanek explained. "If a star can fall short of a supernova and still make a black hole, that would help to explain why we don't see supernovae from the most massive stars." He leads a team of astronomers who published their latest results in the Monthly Notices of the Royal Astronomical Society. Among the galaxies they've been watching is NGC 6946, a spiral galaxy 22 million light-years away that is nicknamed the "Fireworks Galaxy" because supernovae frequently happen there -- indeed, SN 2017eaw, discovered on May 14th, is shining near maximum brightness now. Starting in 2009, one particular star, named N6946-BH1, began to brighten weakly. By 2015, it appeared to have winked out of existence. After the LBT survey for failed supernovas turned up the star, astronomers aimed the Hubble and Spitzer space telescopes to see if it was still there but merely dimmed. They also used Spitzer to search for any infrared radiation emanating from the spot. That would have been a sign that the star was still present, but perhaps just hidden behind a dust cloud. All the tests came up negative. The star was no longer there. By a careful process of elimination, the researchers eventually concluded that the star must have become a black hole. It's too early in the project to know for sure how often stars experience massive fails, but Scott Adams, a former Ohio State student who recently earned his doctorate doing this work, was able to make a preliminary estimate. "N6946-BH1 is the only likely failed supernova that we found in the first seven years of our survey. During this period, six normal supernovae have occurred within the galaxies we've been monitoring, suggesting that 10 to 30 percent of massive stars die as failed supernovae," he said. "This is just the fraction that would explain the very problem that motivated us to start the survey, that is, that there are fewer observed supernovae than should be occurring if all massive stars die that way." To study co-author Krzysztof Stanek, the really interesting part of the discovery is the implications it holds for the origins of very massive black holes -- the kind that the LIGO experiment detected via gravitational waves. (LIGO is the Laser Interferometer Gravitational-Wave Observatory.) It doesn't necessarily make sense, said Stanek, professor of astronomy at Ohio State, that a massive star could undergo a supernova -- a process which entails blowing off much of its outer layers -- and still have enough mass left over to form a massive black hole on the scale of those that LIGO detected. "I suspect it's much easier to make a very massive black hole if there is no supernova," he concluded. Adams is now an astrophysicist at Caltech. Other co-authors were Ohio State doctoral student Jill Gerke and University of Oklahoma astronomer Xinyu Dai. Their research was supported by the National Science Foundation. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. The Large Binocular Telescope is an international collaboration among institutions in the United Sates, Italy and Germany. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.


News Article | May 26, 2017
Site: spaceref.com

Astronomers have watched as a massive, dying star was likely reborn as a black hole. It took the combined power of the Large Binocular Telescope (LBT), and NASA's Hubble and Spitzer space telescopes to go looking for remnants of the vanquished star, only to find that it disappeared out of sight. It went out with a whimper instead of a bang. The star, which was 25 times as massive as our sun, should have exploded in a very bright supernova. Instead, it fizzled out--and then left behind a black hole. "Massive fails" like this one in a nearby galaxy could explain why astronomers rarely see supernovae from the most massive stars, said Christopher Kochanek, professor of astronomy at The Ohio State University and the Ohio Eminent Scholar in Observational Cosmology. As many as 30 percent of such stars, it seems, may quietly collapse into black holes -- no supernova required. "The typical view is that a star can form a black hole only after it goes supernova," Kochanek explained. "If a star can fall short of a supernova and still make a black hole, that would help to explain why we don't see supernovae from the most massive stars." He leads a team of astronomers who published their latest results in the Monthly Notices of the Royal Astronomical Society [paper MNRAS, preprint: astro-ph]. Among the galaxies they've been watching is NGC 6946, a spiral galaxy 22 million light-years away that is nicknamed the "Fireworks Galaxy" because supernovae frequently happen there -- indeed, SN 2017eaw, discovered on May 14th, is shining near maximum brightness now. Starting in 2009, one particular star, named N6946-BH1, began to brighten weakly. By 2015, it appeared to have winked out of existence. After the LBT survey for failed supernovas turned up the star, astronomers aimed the Hubble and Spitzer space telescopes to see if it was still there but merely dimmed. They also used Spitzer to search for any infrared radiation emanating from the spot. That would have been a sign that the star was still present, but perhaps just hidden behind a dust cloud. All the tests came up negative. The star was no longer there. By a careful process of elimination, the researchers eventually concluded that the star must have become a black hole. It's too early in the project to know for sure how often stars experience massive fails, but Scott Adams, a former Ohio State student who recently earned his Ph.D. doing this work, was able to make a preliminary estimate. "N6946-BH1 is the only likely failed supernova that we found in the first seven years of our survey. During this period, six normal supernovae have occurred within the galaxies we've been monitoring, suggesting that 10 to 30 percent of massive stars die as failed supernovae," he said. "This is just the fraction that would explain the very problem that motivated us to start the survey, that is, that there are fewer observed supernovae than should be occurring if all massive stars die that way." To study co-author Krzysztof Stanek, the really interesting part of the discovery is the implications it holds for the origins of very massive black holes -- the kind that the LIGO experiment detected via gravitational waves. (LIGO is the Laser Interferometer Gravitational-Wave Observatory.) It doesn't necessarily make sense, said Stanek, professor of astronomy at Ohio State, that a massive star could undergo a supernova -- a process which entails blowing off much of its outer layers -- and still have enough mass left over to form a massive black hole on the scale of those that LIGO detected. "I suspect it's much easier to make a very massive black hole if there is no supernova," he concluded. Adams is now an astrophysicist at Caltech. Other co-authors were Ohio State doctoral student Jill Gerke and University of Oklahoma astronomer Xinyu Dai. Their research was supported by the National Science Foundation. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. The Large Binocular Telescope is an international collaboration among institutions in the United Sates, Italy and Germany. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C. Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | January 26, 2016
Site: phys.org

Dark matter and dark energy are two of the greatest mysteries of the universe, still perplexing scientists worldwide. Solving these scientific conundrums may require a comprehensive approach in which theories, computations and ground-based observations are complemented by a fleet of spacecraft studying the dark universe. One of the space missions that could be essential to our understanding of these mysteries is European Space Agency's (ESA) Euclid probe, designed to unveil the secrets of dark energy and dark matter by accurately measuring the acceleration of the universe. "Euclid is designed primarily to help us understand the properties of dark energy. However, in doing so, it will utilize the exquisite precision only available to a space-based instrument to make measurements of dark matter over an unprecedented area of the sky. Thus, it will be a real breakthrough in our understanding of both dark matter and dark energy," Ulf Israelsson, NASA Euclid project manager, told Astrowatch.net. The spacecraft is currently in the construction phase after successfully passing its Preliminary Design Review in the Fall of 2015. It will be launched in 2020 on a Soyuz rocket from Europe's Spaceport in Kourou, French Guiana. After liftoff it will be sent into orbit around the sun-Earth L2 point located approximately 1.5 million km from our planet. In order to help us understand dark matter and dark energy, Euclid will employ two primary scientific methods. "The first is weak gravitational lensing, whereby the apparent shapes of background galaxies are distorted by foreground dark matter. The second is galaxy clustering, looking at the three-dimensional distribution of galaxies," Jason Rhodes, NASA Euclid Deputy Project Scientist and the U.S. Science Lead for Euclid, told SpaceFlight Insider. The spacecraft will map the shapes, positions and movements of two billion galaxies, delivering astronomers a vast set of important data for further studies. It is expected to produce numerous deep images and spectra over at least half of the entire sky. To achieve its ambitious scientific goals, Euclid will be equipped with two main instruments: the Visible Imaging Instrument (VIS) and the Near Infrared Spectrometer and Photometer (NISP). These large format cameras will be used to characterize the morphometric, photometric and spectroscopic properties of galaxies. "Euclid will have two instruments. The first is the visible imaging instrument. It will use a single, very wide filter to perform photometry of visible light over a 15,000 square degree area on the sky. The second is the Near Infrared Spectrometer and Photometer. This instrument will use NASA-provided near infrared detectors to perform 3-band photometry in near infrared light over the same 15,000 square degrees as well as providing grism spectroscopy in the near infrared over the same area," Israelsson explained. The mission, which will last six years, will survey the sky in 'step-and-stare' mode. In this mode the telescope points to a position on the sky and imaging and spectroscopic measurements are performed on an area of about 0.5 square degrees around this position. The wide survey will cover 15,000 square degrees of extragalactic sky and the deep survey is expected to cover approximately 40 square degrees, consisting of patches of at least 10 square degrees which are about two magnitudes deeper than the wide-survey. NASA made important contributions to this mission including infrared detectors for one instrument and science and data analysis. "NASA is providing near infrared detectors and associated electronics for the NISP instrument. NASA is also developing the Euclid NASA Science Center at IPAC [Infrared Processing and Analysis Center], a node in Euclid's distributed Science Ground Segment that will process the Euclid data. The third contribution is in support of about 70 US scientists who are part of the 1,300 member Euclid Consortium," Rhodes said. Explore further: Euclid mission gets go-ahead to probe Universe's darkest secrets


News Article | April 22, 2016
Site: www.rdmag.com

Astronomers have located a new celestial body named WISEA 1147 and it resides in the TW Hydrae system of stars. This planetary object is approximately 10 million years old and estimated to be roughly five to 10 times the mass of Jupiter, according to the announcement from the University of Toledo. Its classification, though, is a lightweight star called a brown dwarf instead of a planet. NASA adds that its brown dwarf origins are more likely due to the fact that, “planets require at least 10 million years to form, and probably longer to get themselves kicked out of a star system.” Brown dwarfs form in a similar manner to stars but don’t have the mass needed to combine atoms at their cores and emit starlight needed to shine. "We are at the beginning of what will become a hot field – trying to determine the nature of the free-floating population and how many are planets versus brown dwarfs," said co-author Davy Kirkpatrick of NASA's Infrared Processing and Analysis Center, or IPAC, at the California Institute of Technology in Pasadena, in a statement. The research team comprised of astronomers from the University of Toledo, California Institute of Technology, and UCLA discovered WISEA 1147 after sorting through images taken with NASA’s Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). Both tools sense infrared light, which is well suited for finding brown dwarfs since heat signatures light up through infrared images, according to NASA. Ultimately, this discovery will help scientists develop a better understanding of chemical and weather compositions of these exoplanets as well as determining how they form without external factors like a host sun or accompanying planets. The study will be published in The Astrophysics Journal. Establish your company as a technology leader! For more than 50 years, the R&D 100 Awards have showcased new products of technological significance. You can join this exclusive community! Learn more.


News Article | January 20, 2016
Site: news.yahoo.com

This artistic rendering provided by California Institute of Technology shows the distant view from Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Scientists reported Wednesday, Jan. 20, 2016, they finally have "good evidence" for Planet X, a true ninth planet on the fringes of our solar system. (R. Hurt/Infrared Processing and Analysis Center/Courtesy of California Institute of Technology via AP) More CAPE CANAVERAL, Fla. (AP) — The solar system may have a ninth planet after all. This one is 5,000 times bigger than outcast Pluto and billions of miles farther away, say scientists who presented "good evidence" for a long-hypothesized Planet X on Wednesday. The gas giant is thought to be almost as big as its nearest planetary neighbor Neptune, quite possibly with rings and moons. It's so distant that it would take a mind-blowing 10,000 to 20,000 years to circle the sun. Planet 9, as the pair of California Institute of Technology researchers calls it, hasn't been spotted yet. They base their prediction on mathematical and computer modeling, and anticipate its discovery via telescope within five years or less. The two reported their research Wednesday in the Astronomical Journal because they want people to help them look for it. "We could have stayed quiet and quietly spent the next five years searching the skies ourselves and hoping to find it. But I would rather somebody find it sooner, than me find it later," astronomer Mike Brown told The Associated Press. "I want to see it. I want to see what it looks like. I want to understand where it is, and I think this will help." Brown and planetary scientist Konstantin Batygin feel certain about their prediction, which at first seemed unbelievable to even them. "For the first time in more than 150 years, there's good evidence that the planetary census of the solar system is incomplete," Batygin said, referring to Neptune's discovery as Planet 8. Once it's detected, Brown insists there will be no Pluto-style planetary debate. Brown ought to know; he's the so-called Pluto killer who helped lead the charge against Pluto's planetary status in 2006. (Once Planet 9, Pluto is now officially considered a dwarf planet.) "THIS is what we mean when we say the word 'planet,' " Brown said. Brown and Batygin believe it's big — 10 times more massive than Earth — and unlike Pluto, dominates its cosmic neighborhood. Pluto is a gravitational slave to Neptune, they pointed out. Another scientist, Alan Stern, said he's withholding judgment on the planet prediction. He is the principal scientist for NASA's New Horizons spacecraft, which buzzed Pluto last summer in the first-ever visit from Planet Earth. He still sees Pluto as a real planet — not a second-class dwarf. "This kind of thing comes around every few years. To date, none of those predicts have been borne out by discoveries," Stern said in an email Wednesday. "I'd be very happy if the Brown-Batygin were the exception to the rule, but we'll have to wait and see. Prediction is not discovery." Brown and Batygin shaped their calculation on the fact that six objects in the icy Kuiper Belt, or Twilight Zone on the far reaches of the solar system, appear to have orbits influenced by only one thing: a real planet. The vast, mysterious Kuiper Belt is home to Pluto as well. Brown actually discovered one of these six objects more than a decade ago, Sedna, a large minor planet. "What we have found is a gravitational signature of Planet 9 lurking in the outskirts of the solar system,' Batygin said. The actual discovery, he noted, will be "era-defining." Added Brown: "We have felt a great disturbance in the force." Scott Sheppard of the Carnegie Institution for Science in Washington said Brown and Batygin's effort takes his own findings to "the next level." Two years ago, he and a colleague suggested a possible giant planet. "I find this new work very exciting," Sheppard said in an email. "It makes the distant Super-Earth planet in our solar system much more real. I would say the odds just went from 50 percent to 75 percent that this distant massive planet is real." Depending on where this Planet 9 is in its egg-shaped orbit, a space telescope may be needed to confirm its presence, the researchers said. Or good backyard telescopes may spot it, they noted, if the planet is relatively closer to us in its swing around the sun. It's an estimated 20 billion to 100 billion miles away. The Caltech researchers prefer calling it Planet 9, versus the historical term Planet X. The latter smacks of "aliens and the imminent destruction of the Earth," according to Brown.


News Article | February 15, 2017
Site: phys.org

"There are just over four light-years between Neptune and Proxima Centauri, the nearest star, and much of this vast territory is unexplored," said lead researcher Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Because there's so little sunlight, even large objects in that region barely shine in visible light. But by looking in the infrared, WISE may have imaged objects we otherwise would have missed." WISE scanned the entire sky between 2010 and 2011, producing the most comprehensive survey at mid-infrared wavelengths currently available. With the completion of its primary mission, WISE was shut down in 2011. It was then reactivated in 2013 and given a new mission assisting NASA's efforts to identify potentially hazardous near-Earth objects (NEOs), which are asteroids and comets on orbits that bring them into the vicinity of Earth's orbit. The mission was renamed the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). The new website uses the data to search for unknown objects in and beyond our own solar system. In 2016, astronomers at Caltech in Pasadena, California, showed that several distant solar system objects possessed orbital features indicating they were affected by the gravity of an as-yet-undetected planet, which the researchers nicknamed "Planet Nine." If Planet Nine—also known as Planet X—exists and is as bright as some predictions, it could show up in WISE data. The search also may discover more distant objects like brown dwarfs, sometimes called failed stars, in nearby interstellar space. "Brown dwarfs form like stars but evolve like planets, and the coldest ones are much like Jupiter," said team member Jackie Faherty, an astronomer at the American Museum of Natural History in New York. "By using Backyard Worlds: Planet 9, the public can help us discover more of these strange rogue worlds." Unlike more distant objects, those in or closer to the solar system appear to move across the sky at different rates. The best way to discover them is through a systematic search of moving objects in WISE images. While parts of this search can be done by computers, machines are often overwhelmed by image artifacts, especially in crowded parts of the sky. These include brightness spikes associated with star images and blurry blobs caused by light scattered inside WISE's instruments. Backyard Worlds: Planet 9 relies on human eyes because we easily recognize the important moving objects while ignoring the artifacts. It's a 21st-century version of the technique astronomer Clyde Tombaugh used to find Pluto in 1930, a discovery made 87 years ago this week. On the website, people around the world can work their way through millions of "flipbooks," which are brief animations showing how small patches of the sky changed over several years. Moving objects flagged by participants will be prioritized by the science team for follow-up observations by professional astronomers. Participants will share credit for their discoveries in any scientific publications that result from the project. "Backyard Worlds: Planet 9 has the potential to unlock once-in-a-century discoveries, and it's exciting to think they could be spotted first by a citizen scientist," said team member Aaron Meisner, a postdoctoral researcher at the University of California, Berkeley, who specializes in analyzing WISE images. Backyard Worlds: Planet 9 is a collaboration between NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University, the Space Telescope Science Institute in Baltimore, and Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the internet. NASA's Jet Propulsion Laboratory in Pasadena, California, manages and operates WISE for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colorado. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech, which manages JPL for NASA. Explore further: NEOWISE mission spies one comet, maybe two


News Article | August 12, 2016
Site: boingboing.net

Here's a wonderful feature about my favorite constellation and the galaxy's most awesome telescope (at least one of them!) from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. Like cosmic ballet dancers, the stars of the Pleiades cluster are spinning. But these celestial dancers are all twirling at different speeds. Astronomers have long wondered what determines the rotation rates of these stars. By watching these stellar dancers, NASA's Kepler space telescope during its K2 mission has helped amass the most complete catalog of rotation periods for stars in a cluster. This information can help astronomers gain insight into where and how planets form around these stars, and how such stars evolve. "We hope that by comparing our results to other star clusters, we will learn more about the relationship between a star’s mass, its age, and even the history of its solar system," said Luisa Rebull, a research scientist at the Infrared Processing and Analysis Center at Caltech in Pasadena, California. She is the lead author of two new papers and a co-author on a third paper about these findings, all being published in the Astronomical Journal. The Pleiades star cluster is one of the closest and most easily seen star clusters, residing just 445 light-years away from Earth, on average. At about 125 million years old, these stars -- known individually as Pleiads -- have reached stellar "young adulthood." In this stage of their lives, the stars are likely spinning the fastest they ever will. As a typical star moves further along into adulthood, it loses some zip due to the copious emission of charged particles known as a stellar wind (in our solar system, we call this the solar wind). The charged particles are carried along the star’s magnetic fields, which overall exerts a braking effect on the rotation rate of the star. Rebull and colleagues sought to delve deeper into these dynamics of stellar spin with Kepler. Given its field of view on the sky, Kepler observed approximately 1,000 stellar members of the Pleiades over the course of 72 days. The telescope measured the rotation rates of more than 750 stars in the Pleiades, including about 500 of the lowest-mass, tiniest, and dimmest cluster members, whose rotations could not previously be detected from ground-based instruments. Kepler measurements of starlight infer the spin rate of a star by picking up small changes in its brightness. These changes result from "starspots" which, like the more-familiar sunspots on our sun, form when magnetic field concentrations prevent the normal release of energy at a star’s surface. The affected regions become cooler than their surroundings and appear dark in comparison. As stars rotate, their starspots come in and out of Kepler’s view, offering a way to determine spin rate. Unlike the tiny, sunspot blemishes on our middle-aged sun, starspots can be gargantuan in stars as young as those in the Pleiades because stellar youth is associated with greater turbulence and magnetic activity. These starspots trigger larger brightness decreases, and make spin rate measurements easier to obtain. During its observations of the Pleiades, a clear pattern emerged in the data: More massive stars tended to rotate slowly, while less massive stars tended to rotate rapidly. The big-and-slow stars' periods ranged from one to as many as 11 Earth-days. Many low-mass stars, however, took less than a day to complete a pirouette. (For comparison, our sedate sun revolves fully just once every 26 days.) The population of slow-rotating stars includes some ranging from a bit larger, hotter and more massive than our sun, down to other stars that are somewhat smaller, cooler and less massive. On the far end, the fast-rotating, fleet-footed, lowest-mass stars possess as little as a tenth of our sun’s mass. "In the 'ballet' of the Pleiades, we see that slow rotators tend to be more massive, whereas the fastest rotators tend to be very light stars," said Rebull. The main source of these differing spin rates is the internal structure of the stars, Rebull and colleagues suggest. Larger stars have a huge core enveloped in a thin layer of stellar material undergoing a process called convection, familiar to us from the circular motion of boiling water. Small stars, on the other hand, consist almost entirely of convective, roiling regions. As stars mature, the braking mechanism from magnetic fields more easily slows the spin rate of the thin, outermost layer of big stars than the comparatively thick, turbulent bulk of small stars. Thanks to the Pleiades’ proximity, researchers think it should be possible to untangle the complex relationships between stars’ spin rates and other stellar properties. Those stellar properties, in turn, can influence the climates and habitability of a star’s hosted exoplanets. For instance, as spinning slows, so too does starspot generation, and the solar storms associated with starspots. Fewer solar storms means less intense, harmful radiation blasting into space and irradiating nearby planets and their potentially emerging biospheres. "The Pleiades star cluster provides an anchor for theoretical models of stellar rotation going both directions, younger and older," said Rebull. "We still have a lot we want to learn about how, when and why stars slow their spin rates and hang up their 'dance shoes,' so to speak." Rebull and colleagues are now analyzing K2 mission data from an older star cluster, Praesepe, popularly known as the Beehive Cluster, to further explore this phenomenon in stellar structure and evolution. "We’re really excited that K2 data of star clusters, such as the Pleiades, have provided astronomers with a bounty of new information and helped advance our knowledge of how stars rotate throughout their lives," said Steve Howell, project scientist for the K2 mission at NASA’s Ames Research Center in Moffett Field, California. The K2 mission’s approach to studying stars employs the Kepler spacecraft's ability to precisely observe miniscule changes in starlight. Kepler’s primary mission ended in 2013, but more exoplanet and astrophysics observations continue with the K2 mission, which began in 2014. Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.


News Article | October 26, 2016
Site: astrobiology.com

The dusty side of the Sword of Orion is illuminated in this striking infrared image from ESA's Hershel Space Observatory. Within the inset image, the emission from ionized carbon atoms (C+) is overlaid in yellow. Life exists in a myriad of wondrous forms, but if you break any organism down to its most basic parts, it's all the same stuff: carbon atoms connected to hydrogen, oxygen, nitrogen and other elements. But how these fundamental substances are created in space has been a longstanding mystery. Now, astronomers better understand how molecules form that are necessary for building other chemicals essential for life. Thanks to data from the European Space Agency's Herschel Space Observatory, scientists have found that ultraviolet light from stars plays a key role in creating these molecules, rather than "shock" events that create turbulence, as was previously thought. Scientists studied the ingredients of carbon chemistry in the Orion Nebula, the closest star-forming region to Earth that forms massive stars. They mapped the amount, temperature and motions of the carbon-hydrogen molecule (CH, or "methylidyne" to chemists), the carbon-hydrogen positive ion (CH+) and their parent: the carbon ion (C+). An ion is an atom or molecule with an imbalance of protons and electrons, resulting in a net charge. "On Earth, the Sun is the driving source of almost all the life on Earth. Now, we have learned that starlight drives the formation of chemicals that are precursors to chemicals that we need to make life," said Patrick Morris, first author of the paper and researcher at the Infrared Processing and Analysis Center at Caltech in Pasadena. In the early 1940s, CH and CH+ were two of the first three molecules ever discovered in interstellar space. In examining molecular clouds -- assemblies of gas and dust -- in Orion with Herschel, scientists were surprised to find that CH+ is emitting rather than absorbing light, meaning it is warmer than the background gas. The CH+ molecule needs a lot of energy to form and is extremely reactive, so it gets destroyed when it interacts with the background hydrogen in the cloud. Its warm temperature and high abundance are therefore quite mysterious. Why, then, is there so much CH+ in molecular clouds such as the Orion Nebula? Many studies have tried to answer this question before, but their observations were limited because few background stars were available for studying. Herschel probes an area of the electromagnetic spectrum -- the far infrared, associated with cold objects -- that no other space telescope has reached before, so it could take into account the entire Orion Nebula instead of individual stars within. The instrument they used to obtain their data, HIFI, is also extremely sensitive to the motion of the gas clouds. One of the leading theories about the origins of basic hydrocarbons has been that they formed in "shocks," events that create a lot of turbulence, such as exploding supernovae or young stars spitting out material. Areas of molecular clouds that have a lot of turbulence generally create shocks. Like a large wave hitting a boat, shock waves cause vibrations in material they encounter. Those vibrations can knock electrons off atoms, making them ions, which are more likely to combine. But the new study found no correlation between these shocks and CH+ in the Orion Nebula. Herschel data show that these CH+ molecules were more likely created by the ultraviolet emission of very young stars in the Orion Nebula, which, compared to the sun, are hotter, far more massive and emit much more ultraviolet light. When a molecule absorbs a photon of light, it becomes "excited" and has more energy to react with other particles. In the case of a hydrogen molecule, the hydrogen molecule vibrates, rotates faster or both when hit by an ultraviolet photon. It has long been known that the Orion Nebula has a lot of hydrogen gas. When ultraviolet light from large stars heats up the surrounding hydrogen molecules, this creates prime conditions for forming hydrocarbons. As the interstellar hydrogen gets warmer, carbon ions that originally formed in stars begin to react with the molecular hydrogen, creating CH+. Eventually the CH+ captures an electron to form the neutral CH molecule. "This is the initiation of the whole carbon chemistry," said John Pearson, researcher at NASA's Jet Propulsion Laboratory, Pasadena, California, and study co-author. "If you want to form anything more complicated, it goes through that pathway." Scientists combined Herschel data with models of molecular formation and found that ultraviolet light is the best explanation for how hydrocarbons form in the Orion Nebula. The findings have implications for the formation of basic hydrocarbons in other galaxies as well. It is known that other galaxies have shocks, but dense regions in which ultraviolet light dominates heating and chemistry may play the key role in creating fundamental hydrocarbon molecules there, too. "It's still a mystery how certain molecules get excited in the cores of galaxies," Pearson said. "Our study is a clue that ultraviolet light from massive stars could be driving the excitation of molecules there, too." Reference: "Herschel/HIFI Spectral Mapping of C+, CH+, and CH in Orion BN/KL: The Prevailing Role of Ultraviolet Irradiation in CH+ Formation," Patrick W. Morris et al., 2016, to appear in the Astrophysical Journal [http://apj.aas.org, preprint: https://arxiv.org/abs/1604.05805]. Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant as expected, scientists continue to analyze its data. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, California. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of IPAC, supports the U.S. astronomical community. Caltech manages JPL for NASA.


News Article | February 15, 2017
Site: www.eurekalert.org

NASA is inviting the public to help search for possible undiscovered worlds in the outer reaches of our solar system and in neighboring interstellar space. A new website, called Backyard Worlds: Planet 9, lets everyone participate in the search by viewing brief movies made from images captured by NASA's Wide-field Infrared Survey Explorer (WISE) mission. The movies highlight objects that have gradually moved across the sky. "There are just over four light-years between Neptune and Proxima Centauri, the nearest star, and much of this vast territory is unexplored," said lead researcher Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Because there's so little sunlight, even large objects in that region barely shine in visible light. But by looking in the infrared, WISE may have imaged objects we otherwise would have missed." WISE scanned the entire sky between 2010 and 2011, producing the most comprehensive survey at mid-infrared wavelengths currently available. With the completion of its primary mission, WISE was shut down in 2011. It was then reactivated in 2013 and given a new mission assisting NASA's efforts to identify potentially hazardous near-Earth objects (NEOs), which are asteroids and comets on orbits that bring them into the vicinity of Earth's orbit. The mission was renamed the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). The new website uses the data to search for unknown objects in and beyond our own solar system. In 2016, astronomers at Caltech in Pasadena, California, showed that several distant solar system objects possessed orbital features indicating they were affected by the gravity of an as-yet-undetected planet, which the researchers nicknamed "Planet Nine." If Planet Nine -- also known as Planet X -- exists and is as bright as some predictions, it could show up in WISE data. The search also may discover more distant objects like brown dwarfs, sometimes called failed stars, in nearby interstellar space. "Brown dwarfs form like stars but evolve like planets, and the coldest ones are much like Jupiter," said team member Jackie Faherty, an astronomer at the American Museum of Natural History in New York. "By using Backyard Worlds: Planet 9, the public can help us discover more of these strange rogue worlds." Unlike more distant objects, those in or closer to the solar system appear to move across the sky at different rates. The best way to discover them is through a systematic search of moving objects in WISE images. While parts of this search can be done by computers, machines are often overwhelmed by image artifacts, especially in crowded parts of the sky. These include brightness spikes associated with star images and blurry blobs caused by light scattered inside WISE's instruments. Backyard Worlds: Planet 9 relies on human eyes because we easily recognize the important moving objects while ignoring the artifacts. It's a 21st-century version of the technique astronomer Clyde Tombaugh used to find Pluto in 1930, a discovery made 87 years ago this week. On the website, people around the world can work their way through millions of "flipbooks," which are brief animations showing how small patches of the sky changed over several years. Moving objects flagged by participants will be prioritized by the science team for follow-up observations by professional astronomers. Participants will share credit for their discoveries in any scientific publications that result from the project. "Backyard Worlds: Planet 9 has the potential to unlock once-in-a-century discoveries, and it's exciting to think they could be spotted first by a citizen scientist," said team member Aaron Meisner, a postdoctoral researcher at the University of California, Berkeley, who specializes in analyzing WISE images. Backyard Worlds: Planet 9 is a collaboration between NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University, the Space Telescope Science Institute in Baltimore, and Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the internet. NASA's Jet Propulsion Laboratory in Pasadena, California, manages and operates WISE for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colorado. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech, which manages JPL for NASA. For more information about Backyard Worlds: Planet 9, visit: For more information about NASA's WISE mission, visit:

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