Universe Sandbox

Universe Sandbox Legacy => Universe Sandbox 2008 | Discussion => Topic started by: Naru523 on September 19, 2009, 07:14:22 AM

Title: BD +20307
Post by: Naru523 on September 19, 2009, 07:14:22 AM
BD +20307 is a close binary star system approximately 300 light-years away in the constellation Aries. Both
stars are considered to be Solar-type stars that are slightly more massive than the Sun. The two stars differ in effective temperature by only ~250 K and have a mass ratio of 0.91. The two orbit a common center of mass every 3.42 days. Within the spectra of the two stars the Li lines show different equivalent widths. The Li 6707 line though weak is detected only from the primary star, suggesting that it is older than 1 Gyr. If so, the large amount of zodiacal dust around the binary must be from a very large and recent collision of planetesimals.

The dust cloud orbiting BD+20307 has about 1 million times more dust than is orbiting our Sun. Furthermore, the dust is made up of extremely tiny particles, and its temperature is over 100 K, which is unusually high. It is hypothesized that, within the past few hundred thousand years and perhaps much more recently, these particles were formed by a collision between two bodies similar to Earth. "It's as if Earth and Venus collided," said Prof. Benjamin Zuckerman, UCLA professor of physics and astronomy. "Astronomers have never seen anything like this before. Apparently, major catastrophic collisions can take place in a fully mature planetary system." This hypothesis explains why the bulk of this dust has not spiraled into BD +20307, or been pushed out by stellar winds yet.[4] The National Science Foundation (NSF), NASA, Tennessee State University (TSU) and the State of Tennessee funded the work by Zuckerman and his collaborators.

Scource: http://en.wikipedia.org/wiki/BD_%2B20%C2%B0307

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