[LINK] Pop goes the world(s)

[rfmcdonald]

I got this news item from james_nicoll.

Two terrestrial planets orbiting a mature sun-like star [of BD +20°307] some 300 light-years from Earth recently suffered a violent collision, astronomers at UCLA, Tennessee State University and the California Institute of Technology will report in a December issue of the Astrophysical Journal, the premier journal of astronomy and astrophysics.

"It's as if Earth and Venus collided with each other," said Benjamin Zuckerman, UCLA professor of physics and astronomy and a co-author on the paper. "Astronomers have never seen anything like this before. Apparently, major catastrophic collisions can take place in a fully mature planetary system."

"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 Tennessee State University (TSU). "A massive disk of infrared-emitting dust circling the star provides silent testimony to this sad fate."

[. . .]

"The patterns of element abundances in the stars show that they are much older than a few hundred million years, as originally thought," Fekel said. "Instead, the binary system appears to have an age of several billion years, comparable to our solar system."

"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."