BD+20 307, in the constellation Aries

Jul 21, 2005 16:23 GMT  ·  By

Astronomers report tremendous quantities of warm dusty debris surrounding a star with luminosity and mass similar to the sun's, but located 300 light-years from Earth. The extraordinary nature of the dust indicates a violent history of cosmic collisions between asteroids and comets, or perhaps even between planets. The discovery is published July 21 in Nature.

"What is so amazing is that the amount of dust around this star is approximately 1 million times greater than the dust around the sun," said Eric Becklin, a UCLA professor of physics and astronomy, member of NASA's Astrobiology Institute, and co-author of the Nature paper. "It's likely there was a cosmic catastrophe, and a time of heavy bombardment, where large asteroids collided in the last few thousand years or less. It's incredible what must be going on."

Unlike hundreds of other stars with dust, where the dust is far from the star - equivalent to beyond the orbit of Pluto - this dust is orbiting in close to the star, where Earth-like planets are most likely to be, said Inseok Song, a former UCLA research scientist who is now an astronomer with the Gemini Observatory in Hawaii, and lead author of the paper.

Was Song surprised to see so much dust so near to the star, which is known as BD+20 307, and is in the constellation Aries?

"Definitely," he said. "I expected to find a much weaker excess because dust close to the star can't survive long."

"The amount of warm dust near BD+20 307 is so unprecedented I wouldn't be surprised if it was the result of a massive collision between planet-size objects, for example, a collision like the one which many scientists believe formed Earth's moon," said Benjamin Zuckerman, UCLA professor of physics and astronomy, member of NASA's Astrobiology Institute, and a co-author of the paper. "According to this model, the early Earth was struck by a Mars-size object that generated an immense fountain of hot magma, some of which condensed to form the moon. But if even a small percentage of this magma escaped into orbit around the sun, it could have led to a condition such as we now witness at BD+20 307."

"This looks similar to our own solar system, and may well lead to a greater understanding of how our solar system formed," said Becklin, who is chief scientist for NASA's Stratospheric Observatory for Infrared Astronomy project. "It is very likely there are planets orbiting this star."

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