A Planet in Progress?March 27, 2008Scientists are one step closer to understanding how new planets form, thanks to research funded by the National Science Foundation (NSF) and carried out by a team of astrophysicists at the American Museum of Natural History. Ben R. Oppenheimer, assistant curator in the museum's Department of Astrophysics, and his colleagues have used the Lyot Project coronograph attached to a U.S. Air Force telescope on Maui, Hawaii, to construct an image of material that seems to be coalescing into a body from the gas and dust cloud surrounding AB Aurigae, a well-studied star. The body is either a planet or a brown dwarf--something with mass between a star or a planet. Brown dwarfs have been found orbiting stars since a team that included Oppenheimer first discovered one in 1995. The research results, accepted for publication in June's Astrophysical Journal, represent a significant step toward direct imaging and the study of exoplanets, which orbit stars other than the Sun, and may advance theories of planet and brown dwarf formations. "The research builds upon Dr. Openheimer's past successes in the detection of a brown dwarf and several debris disks and take advantage of an improved, deformable, secondary mirror which was installed at the telescope facility in 2006," said NSF Program Manager Julian Christou. "The image produced speaks directly to the biggest, unresolved question of planet formation--how the thick disk of debris and gas evolves into a thin, dusty region with planets." Young stars generally have a lot of material caught in their gravitational pull--material that organizes itself into a disc over time. Astronomers believe planets form in this disc. The image produced by Oppenheimer's team shows a horseshoe-shaped void in the disc with a bright point appearing as a dot in the void. "The deficit of material could be due to a planet forming and sucking material onto it, coalescing into a small point in the image and clearing material in the immediate surroundings," Oppenheimer said. "It seems to be indicative of the formation of a small body, either a planet or a brown dwarf." AB Aurigae is well-studied because it is young, between one and three million years old, and can therefore provide information on how stars and objects that orbit them form. One unresolved question about planet formation is how the initial thick, gas-rich disk of debris evolves into a thin, dusty region with planets. The observation of stars slightly older than AB Aurigae shows that at some point the gas is removed, but no one knows how this happens. AB Aurigae could be in an intermediate stage, where the gas is being cleared out from the center, leaving mainly dust behind. "More detailed observations of this star can help solve questions about how some planets form, and can possibly test competing theories," says Oppenheimer. And if this object is a brown dwarf, our understanding of them must be revamped as brown dwarfs are not believed to form in circumstellar materials, Oppenheimer said. The National Science Foundation |
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| Related Brown Dwarf Current Events and Brown Dwarf News Articles Stellar still births The systematics of celestial bodies apparently needs to be revised. Researchers at the Argelander Institute of Astronomy of the University of Bonn have discovered that brown dwarfs need to be treated as a separate class in addition to stars and planets. Astonomers find tiny planet orbiting tiny star An international team of astronomers led by David Bennett of the University of Notre Dame has discovered an extra-solar planet of about three Earth masses orbiting a star with a mass so low that its core may not be large enough to maintain nuclear reactions. The result was presented Monday (June 2) at the American Astronomical Society annual meeting in St. Louis. Astronomers Weigh the Coldest Brown Dwarfs with Astronomy's Sharpest Eyes Astronomers have used ultrasharp images obtained with the Keck Telescope and Hubble Space Telescope to determine for the first time the masses of the coldest class of "failed stars," a.k.a. brown dwarfs. Finally, the 'Planet' in Planetary Nebulae? Astronomers at the University of Rochester, home to one of the world's largest groups of planetary nebulae specialists, have announced that low-mass stars and possibly even super-Jupiter-sized planets may be responsible for creating some of the most breathtaking objects in the sky. XO-3b: Supersized planet or oasis in the 'brown dwarf desert'? The latest find from an international planet-hunting team of amateur and professional astronomers is one of the oddest extrasolar planets ever cataloged -- a mammoth orb more than 13 times the mass of Jupiter that orbits its star in less than four days. 28 new planets, 7 new brown dwarfs reported by California, Carnegie team The world's largest and most prolific team of planet hunters announced today (Monday, May 28) the discovery of 28 new planets outside our solar system, increasing to 236 the total number of known exoplanets. A Brown Dwarf Joins the Jet-Set Jets of matter have been discovered around a very low mass 'failed star', mimicking a process seen in young stars. This suggests that these 'brown dwarfs' form in a similar manner to normal stars but also that outflows are driven out by objects as massive as hundreds of millions of solar masses down to Jupiter-sized objects. Hubble finds 16 candidate extrasolar planets far across our Galaxy The NASA/ESA Hubble Space Telescope has discovered 16 extrasolar planet candidates that are orbiting a variety of distant stars. In accomplishing this, Hubble looked farther into our Milky Way galaxy than has ever successfully been done before in searching for extrasolar planets. Scientists snap images of first brown dwarf in planetary system Scientists using NASA's Spitzer Space Telescope have discovered and directly imaged a small brown dwarf star, 50 times the mass of Jupiter, orbiting with a planet around a Sun-like star. Planet or failed star? One of smallest stellar companions seen by Hubble Astronomers using the NASA/ESA Hubble Space Telescope have photographed one of the smallest objects ever seen around a normal star beyond our Sun. Weighing in at 12 times the mass of Jupiter, the object is small enough to be a planet. More Brown Dwarf Current Events and Brown Dwarf News Articles |
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