Artist's Conception of Forming Flanet (image) Harvard-Smithsonian Center for Astrophysics Caption This artist's conception shows a planet forming from a disk of gas and dust surrounding a young star. New research finds that exoplanets can be divided into three groups – terrestrials, gas giants, and mid-sized "gas dwarfs" – based on how their host stars tend to fall into three distinct groups defined by their compositions. Credit David A. Aguilar (CfA) Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.