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News Article
Site: http://phys.org/space-news/

Researchers initially classified the star as elderly, perhaps a red supergiant. But a new study by a NASA-led team of researchers suggests that the object, labeled IRAS 19312+1950, might be something quite different - a protostar, a star still in the making. "Astronomers recognized this object as noteworthy around the year 2000 and have been trying ever since to decide how far along its development is," said Martin Cordiner, an astrochemist working at NASA's Goddard Space Flight Center in Greenbelt, Maryland. He is the lead author of a paper in the Astrophysical Journal describing the team's findings, from observations made using NASA's Spitzer Space Telescope and ESA's Herschel Space Observatory. Located more than 12,000 light-years from Earth, the object first stood out as peculiar when it was observed at particular radio frequencies. Several teams of astronomers studied it using ground-based telescopes and concluded that it is an oxygen-rich star about 10 times as massive as the sun. The question was: What kind of star? Some researchers favor the idea that the star is evolved - past the peak of its life cycle and on the decline. For most of their lives, stars obtain their energy by fusing hydrogen in their cores, as the sun does now. But older stars have used up most of their hydrogen and must rely on heavier fuels that don't last as long, leading to rapid deterioration. Two early clues - intense radio sources called masers - suggested the star was old. In astronomy, masers occur when the molecules in certain kinds of gases get revved up and emit a lot of radiation over a very limited range of frequencies. The result is a powerful radio beacon - the microwave equivalent of a laser. One maser observed with IRAS 19312+1950 is almost exclusively associated with late-stage stars. This is the silicon oxide maser, produced by molecules made of one silicon atom and one oxygen atom. Researchers don't know why this maser is nearly always restricted to elderly stars, but of thousands of known silicon oxide masers, only a few exceptions to this rule have been noted. Also spotted with the star was a hydroxyl maser, produced by molecules comprised of one oxygen atom and one hydrogen atom. Hydroxyl masers can occur in various kinds of astronomical objects, but when one occurs with an elderly star, the radio signal has a distinctive pattern - it's especially strong at a frequency of 1612 megahertz. That's the pattern researchers found in this case. Even so, the object didn't entirely fit with evolved stars. Especially puzzling was the smorgasbord of chemicals found in the large cloud of material surrounding the star. A chemical-rich cloud like this is typical of the regions where new stars are born, but no such stellar nursery had been identified near this star. Scientists initially proposed that the object was an old star surrounded by a surprising cloud typical of the kind that usually accompanies young stars. Another idea was that the observations might somehow be capturing two objects: a very old star and an embryonic cloud of star-making material in the same field. Cordiner and his colleagues began to reconsider the object, conducting observations using ESA's Herschel Space Observatory and analyzing data gathered earlier with NASA's Spitzer Space Telescope. Both telescopes operate at infrared wavelengths, which gave the team new insight into the gases, dust and ices in the cloud surrounding the star. The additional information leads Cordiner and colleagues to think the star is in a very early stage of formation. The object is much brighter than it first appeared, they say, emitting about 20,000 times the energy of our sun. The team found large quantities of ices made from water and carbon dioxide in the cloud around the object. These ices are located on dust grains relatively close to the star, and all this dust and ice blocks out starlight making the star seem dimmer than it really is. In addition, the dense cloud around the object appears to be collapsing, which happens when a growing star pulls in material. In contrast, the material around an evolved star is expanding and is in the process of escaping to the interstellar medium. The entire envelope of material has an estimated mass of 500 to 700 suns, which is much more than could have been produced by an elderly or dying star. "We think the star is probably in an embryonic stage, getting near the end of its accretion stage - the period when it pulls in new material to fuel its growth," said Cordiner. Also supporting the idea of a young star are the very fast wind speeds measured in two jets of gas streaming away from opposite poles of the star. Such jets of material, known as a bipolar outflow, can be seen emanating from young or old stars. However, fast, narrowly focused jets are rarely observed in evolved stars. In this case, the team measured winds at the breakneck speed of at least 200,000 miles per hour (90 kilometers per second) - a common characteristic of a protostar. Still, the researchers acknowledge that the object is not a typical protostar. For reasons they can't explain yet, the star has spectacular features of both a very young and a very old star. "No matter how one looks at this object, it's fascinating, and it has something new to tell us about the life cycles of stars," said Steven Charnley, a Goddard astrochemist and co-author of the paper. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission, whose science operations are conducted at the Spitzer Science Center. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Herschel is an ESA space observatory with science instruments provided by European-led principal investigator consortia and with important participation from NASA. More information: On the Nature of the Enigmatic Object IRAS 19312+1950: A Rare Phase of Massive Star Formation? M. A. Cordiner et al., 2016 Sep. 1, Astrophysical Journal iopscience.iop.org/article/10.3847/0004-637X/828/1/51 , On Arxiv: arxiv.org/abs/1607.00432


News Article
Site: http://news.yahoo.com/science/

Some stars may host multiple generations of planets, a dazzling new photo suggests. The newly released image, which was captured by the Very Large Telescope Interferometer (VLTI) in Chile, shows a dusty disk around an old double star called IRAS 08544-4431, which lies about 4,000 light-years from Earth in the southern constellation of Vela (The Sails). Scientists created this video look at the dust-shrouded star to showcase the discovery. This disk is very similar to the planet-forming structures commonly observed around young stars. While it's not clear whether planets actually do take shape around older stars, the new photo — the sharpest ever taken of such a disk around a mature star — hints that this is a possibility, researchers said. [The Strangest Alien Planets (Gallery)] "Our observations and modeling open a new window to study the physics of these disks, as well as stellar evolution in double stars," study co-author Hans Van Winckel, of the Instituut voor Sterrenkunde in Belgium, said in a statement. "For the first time, the complex interactions between close binary systems and their dusty environments can now be resolved in space and time." The scientists used several VLTI telescopes, an associated instrument called the Precision Integrated-Optics Near-infrared Imaging ExpeRiment (PIONIER) and a new high-speed infrared detector to take the photo. "We obtained an image of stunning sharpness — equivalent to what a telescope with a diameter of 150 meters [490 feet] would see," study team member Jacques Kluska, of Exeter University in England, said in the same statement. "The resolution is so high that, for comparison, we could determine the size and shape of a 1-euro coin seen from a distance of 2,000 kilometers [1,240 miles]." The IRAS 08544-4431 system consists of an old red giant star, as well a nearby, younger, "normal" star. The dust that comprises the newly imaged disk was expelled by the red giant, researchers said. "We were also surprised to find a fainter glow that is probably coming from a small accretion disk around the companion star," said study lead author Michael Hillen, also of the Instituut voor Sterrenkunde. "We knew the star was double, but weren't expecting to see the companion directly," Hillen added. "It is really thanks to the jump in performance now provided by the new detector in PIONIER, that we are able to view the very inner regions of this distant system." Hillen and his colleagues are publishing their results in the journal Astronomy & Astrophysics. The VLTI is located at the European Southern Observatory's Paranal Observatory in northern Chile. Follow Elizabeth Howell @howellspace, or Space.com @Spacedotcom. We're also on Facebook and Google+. Original article on Space.com. Copyright 2016 SPACE.com, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


News Article
Site: http://phys.org/space-news/

When some speedy, massive stars plow through space, they can cause material to stack up in front of them in the same way that water piles up ahead of a ship. Called bow shocks, these dramatic, arc-shaped features in space are leading researchers to uncover massive, so-called runaway stars. "Some stars get the boot when their companion star explodes in a supernova, and others can get kicked out of crowded star clusters," said astronomer William Chick from the University of Wyoming in Laramie, who presented his team's new results at the American Astronomical Society meeting in Kissimmee, Florida. "The gravitational boost increases a star's speed relative to other stars." Our own sun is strolling through our Milky Way galaxy at a moderate pace. It is not clear whether our sun creates a bow shock. By comparison, a massive star with a stunning bow shock, called Zeta Ophiuchi (or Zeta Oph), is traveling around the galaxy faster than our sun, at 54,000 mph (24 kilometers per second) relative to its surroundings. Zeta Oph's giant bow shock can be seen in this image from the WISE mission: Both the speed of stars moving through space and their mass contribute to the size and shapes of bow shocks. The more massive a star, the more material it sheds in high-speed winds. Zeta Oph, which is about 20 times as massive as our sun, has supersonic winds that slam into the material in front of it. The result is a pile-up of material that glows. The arc-shaped material heats up and shines with infrared light. That infrared light is assigned the color red in the many pictures of bow shocks captured by Spitzer and WISE. Chick and his team turned to archival infrared data from Spitzer and WISE to identify new bow shocks, including more distant ones that are harder to find. Their initial search turned up more than 200 images of fuzzy red arcs. They then used the Wyoming Infrared Observatory, near Laramie, to follow up on 80 of these candidates and identify the sources behind the suspected bow shocks. Most turned out to be massive stars. The findings suggest that many of the bow shocks are the result of speedy runaways that were given a gravitational kick by other stars. However, in a few cases, the arc-shaped features could turn out to be something else, such as dust from stars and birth clouds of newborn stars. The team plans more observations to confirm the presence of bow shocks. "We are using the bow shocks to find massive and/or runaway stars," said astronomer Henry "Chip" Kobulnicky, also from the University of Wyoming. "The bow shocks are new laboratories for studying massive stars and answering questions about the fate and evolution of these stars." Another group of researchers, led by Cintia Peri of the Argentine Institute of Radio Astronomy, is also using Spitzer and WISE data to find new bow shocks in space. Only instead of searching for the arcs at the onset, they start by hunting down known speedy stars, and then they scan them for bow shocks. "WISE and Spitzer have given us the best images of bow shocks so far," said Peri. "In many cases, bow shocks that looked very diffuse before, can now be resolved, and, moreover, we can see some new details of the structures." Some of the first bow shocks from runaway stars were identified in the 1980s by David Van Buren of NASA's Jet Propulsion Laboratory in Pasadena, California. He and his colleagues found them using infrared data from the Infrared Astronomical Satellite (IRAS), a predecessor to WISE that scanned the whole infrared sky in 1983. Kobulnicky and Chick belong to a larger team of researchers and students studying bow shocks and massive stars, including Matt Povich from the California State Polytechnic University, Pomona. The National Science Foundation funds their research. Images from Spitzer, WISE and IRAS are archived at the NASA Infrared Science Archive housed at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.


News Article | August 30, 2016
Site: http://www.sciencedaily.com/news/top/technology/

For years, astronomers have puzzled over a massive star lodged deep in the Milky Way that shows conflicting signs of being extremely old and extremely young. Researchers initially classified the star as elderly, perhaps a red supergiant. But a new study by a NASA-led team of researchers suggests that the object, labeled IRAS 19312+1950, might be something quite different -- a protostar, a star still in the making.


News Article
Site: http://phys.org/space-news/

Comet P/2016 BA14 was discovered on Jan. 22, 2016, by the University of Hawaii's PanSTARRS telescope on Haleakala, on the island of Maui. It was initially thought to be an asteroid, but follow-up observations by a University of Maryland and Lowell Observatory team with the Discovery Channel Telescope showed a faint tail, revealing that the discovery was, in fact, a comet. The orbit of this newly discovered comet, however, held yet another surprise. Comet P/2016 BA14 follows an unusually similar orbit to that of comet 252P/LINEAR, which was discovered by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research (LINEAR) survey on April 7, 2000. The apparent coincidence may be an indication of twin nature in that comet. P/2016 BA14 is roughly half the size of comet ?252P/LINEAR and might be a fragment that calved off sometime in the larger comet's past. "Comet P/2016 BA14 is possibly a fragment of 252P/LINEAR. The two could be related because their orbits are so remarkably similar," said Paul Chodas, manager of NASA's Center of NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California. "We know comets are relatively fragile things, as in 1993 when comet Shoemaker-Levy 9 was discovered and its pieces linked to a flyby of Jupiter. Perhaps during a previous pass through the inner-solar system, or during a distant flyby of Jupiter, a chunk that we now know of as BA14 might have broken off of 252P." Observations made by the Hubble Space Telescope of comet 252P/LINEAR, and by NASA's Infrared Telescope Facility of comet P/2016 BA14 will further investigate their possible twin nature. Comet 252P/LINEAR, approximately 750 feet (230 meters) in size, will zip past Earth on Monday, March 21 at a range of about 3.3 million miles (5.2 million kilometers). The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 2.2 million miles (3.5 million kilometers). This will be the third closest flyby of a comet in recorded history next to comet D/1770 L1 (Lexell) in 1770 and comet C/1983 H1 (IRAS-Araki-Alcock) in 1983. The time of closest approach for comet 252P/LINEAR on March 21 will be around 5:14 a.m. PDT (8:14 a.m. EDT). The time of closest approach for P/2016 BA14 on March 22 will be around 7:30 a.m. PDT (10:30 a.m. EDT). While both comets will safely fly past at relatively close distances, anyone hoping to see them will need powerful, professional-grade telescopes, due to their relatively small size. The approaches of these two comets will be the closest they come to Earth for the foreseeable future. "March 22 will be the closest comet P/2016 BA14 gets to us for at least the next 150 years," said Chodas. "Comet P/2016 BA14 is not a threat. Instead, it is an excellent opportunity for scientific advancement on the study of comets." The CNEOS website has a complete list of recent and upcoming close approaches, as well as all other data on the orbits of known NEOs, so scientists and members of the media and public can track information on known objects. Explore further: Comet to make close flyby of Red Planet in October 2014

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