By Ron Cowen
Astronomers this week reported the first evidence that a young star is periodically eclipsed by a stream of debris that could be an orbiting cluster of asteroids. The debris may be held in place by a massive, unseen planet, the researchers say. If this interpretation proves correct, scientists may have caught a planetary system during its creation.
About 5 years ago, William Herbst of Wesleyan University in Middletown, Conn., began supervising undergraduates studying the star KH 15D. After analyzing the students’ accumulating data, Herbst and one of his collaborators realized that the star was winking on and off like clockwork.