September 25, 2008
When worlds (really) collide
Two planets orbiting a sun-like star some 300 light-years from Earth suffered a violent collision.
Zuckerman, along with researchers from Tennessee State University (TSU) and the California Institute of Technology were studying a star known as BD+20 307, which is surrounded by a shocking 1 million times more dust than is orbiting our sun. The star is located in the constellation Aries.
“If any life was present on either planet, the massive collision would have wiped out everything in a matter of minutes — the ultimate extinction event,” said co-author Gregory Henry, an astronomer at TSU. “A massive disk of infrared-emitting dust circling the star provides silent testimony to this sad fate.”
Carnegie Institution of Washington astronomer Alycia Weinberger announced in the May 20, 2008, issue of the Astrophysical Journal that BD+20 307 is actually a close binary star — two stars orbiting around their common center of mass.
“The planetary collision in BD+20 307 was not observed directly but rather was inferred from the extraordinary quantity of dust particles that orbit the binary pair at about the same distance as Earth and Venus are from our sun,” Henry said. “If this dust does indeed point to the presence of terrestrial planets, then this represents the first known example of planets of any mass in orbit around a close binary star.”
The astronomers believe the collision took place within the past few hundred thousand years and perhaps much more recently.