Exocomet bonanza

摘要

Exoplanets are used to the limelight-exocomets less so. Now, a fresh crop of comets found around alien stars suggests that these icy dirt balls stalk solar systems across the Milky Way.rnDiscs of debris swirling around young stars clump up to form planets. Asteroids and comets are the leftovers. Comets around alien suns are too small to see directly, so a team led by Barry Welsh at the University of California, Berkeley, looked for the chemical signaturesrnof their tails as they are heated by their host stars.