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How to fail at being a star HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE Posted: July 9, 2004 At the 13th Cambridge Workshop on "Cool Stars, Stellar Systems, and the Sun," Dr. Kevin L. Luhman (Harvard-Smithsonian Center for Astrophysics) announced the discovery of a unique pair of newborn brown dwarfs in orbit around each other. Brown dwarfs are a relatively new class of objects discovered in the mid-1990s that are too small to ignite hydrogen fusion and shine as stars, yet too big to be considered planets. "Are brown dwarfs miniature failed stars, or super-sized planets, or are they altogether different from either stars or planets?" asks Luhman. The unique nature of this new brown dwarf pair has brought astronomers a step closer to the answer.
"In one alternative that has been proposed recently," explains Luhman, "the seeds in an interstellar cloud pull on each other through their gravity, causing a slingshot effect and ejecting some of the seeds from the cloud before they have a chance to grow into stars. These small bodies are what we see as brown dwarfs, according to that hypothesis." Testing these ideas for the birth of brown dwarfs is hampered by the fact that brown dwarfs are normally extremely faint and hard to detect in the sky. For most of their lives, they are not hot enough to ignite hydrogen fusion, so they do not shine brightly like stars, and instead are relatively dim like planets. However, for a short time immediately following their birth, brown dwarfs are relatively bright due to the leftover heat from their formation. As a result, brown dwarfs are easiest to find and study at an age of around 1 million years, which is newborn compared to the 4.5 billion year age of our Sun. Taking advantage of this fact, Luhman searched for newborn brown dwarfs in a cluster of young stars located 540 light-years away in the southern constellation of Chamaeleon. Luhman conducted his search using one of the two 6.5-meter-diameter Magellan telescopes at Las Campanas Observatory in Chile, which are among the largest telescopes in the world. Of the two dozen new brown dwarfs found, most were isolated and floating in space by themselves. However, Luhman discovered one pair of brown dwarfs orbiting each other at a remarkably wide separation. All previously known pairs of brown dwarfs are relatively close to each other, less than half the distance of Pluto from the Sun. But the brown dwarfs in this new pair are much farther apart, about six times the distance of Pluto from the Sun. Because these brown dwarfs are so far apart, they are very weakly bound to each other by gravity, and the slightest tug would permanently separate them. Therefore, Luhman concludes, "The mere existence of this extremely fragile pair indicates that these brown dwarfs were never subjected to the kind of violent gravitational pulls that they would undergo if they had formed as ejected seeds. Instead, it is likely that these baby brown dwarfs formed in the same way as stars, in a relatively gentle and undisturbed manner." Dr. Alan P. Boss (Carnegie Institution) agrees, stating, "Luhman's discovery strengthens the case for the formation mechanism of brown dwarfs being similar to that of stars like the Sun, and hence for brown dwarfs being worthy of being termed 'stars,' even if they are too low in mass to be able to undergo sustained nuclear fusion." The discovery of this binary brown dwarf will be published in an upcoming issue of The Astrophysical Journal. The discovery paper currently is online in PDF format at http://cfa-www.harvard.edu/~kluhman/paper.pdf Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. The Magellan telescopes are operated by the Carnegie Institution of Washington, the University of Arizona, Harvard University, the University of Michigan, and the Massachusetts Institute of Technology. Las Campanas Observatory is operated by the Carnegie Observatories, which was founded in 1904 by George Ellery Hale. It is one of six departments of the private, nonprofit Carnegie Institution of Washington, a pioneering force in basic scientific research since 1902. |
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Columbia Report A reproduction of the official accident investigation report into the loss of the space shuttle Columbia and its crew of seven. U.S. - U.K. - E.U. - Worldwide Apollo 14 DVD In January of 1971, Apollo 14 launched on an ambitious mission to land in the Fra Mauro highlands, a region of the moon more challenging than previous explorations. The flight captured in this DVD set.U.S. Apollo 11 Mission Report Apollo 11 - The NASA Mission Reports Vol. 3 is the first comprehensive study of man's first mission to another world is revealed in all of its startling complexity. Includes DVD!U.S. - U.K. - E.U. - Worldwide STS-115 patch The official crew patch for the STS-115 mission of space shuttle Atlantis to resume orbital construction of the International Space Station.U.S. - U.K. - E.U. - Worldwide Soviet Space For the first time ever available in the West. Rocket & Space Corporation Energia: a complete pictorial history of the Soviet/Russian Space Program from 1946 to the present day all in full color. Available from our store.U.S. - U.K. - E.U. - Worldwide Viking patch This embroidered mission patch celebrates NASA's Viking Project which reached the Red Planet in 1976.U.S. - U.K. - E.U. - Worldwide Apollo 7 DVD For 11 days the crew of Apollo 7 fought colds while they put the Apollo spacecraft through a workout, establishing confidence in the machine what would lead directly to the bold decision to send Apollo 8 to the moon just 2 months later.U.S. - U.K. - E.U. - Worldwide Gemini 12 Gemini 12: The NASA Mission Reports covers the voyage of James Lovell and Buzz Aldrin that capped the Gemini program's efforts to prove the technologies and techniques that would be needed for the Apollo Moon landings. Includes CD-ROM.U.S. - U.K. - E.U. - Worldwide Apollo 11 special patch Special collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.U.S. - U.K. - E.U. - Worldwide Inside Apollo mission control
An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.U.S. The ultimate Apollo 11 DVD This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.U.S. - U.K. - E.U. - Worldwide Next ISS crew
Own a little piece of history with this official patch for the International Space Station's Expedition 11 crew. We'll ship yours today!U.S. Expedition 18 patch & pin The official embroidered patch and lapel pin for the International Space Station Expedition 18 crew is now available to from our stores.NASA 50th anniversary pin Celebrate the 50th anniversary of the U.S. space agency NASA with this lapel pin featuring the official logo.
![]() Columbus mission patch The official astronaut embroidered patch of Atlantis' STS-122 mission that launched the Columbus science lab in February is available to U.S. customers from our store.Project Orion The Orion crew exploration vehicle is NASA's first new human spacecraft developed since the space shuttle a quarter-century earlier. The capsule is one of the key elements of returning astronauts to the Moon.Apollo patches The Apollo Patch Collection: Includes all 12 Apollo mission patches plus the Apollo Program Patch. Save over 20% off the Individual price. U.S. STORE |
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