"Exploring the Relationship Between Stellar Mass and Planet Formation"
Over 160 nearby stars are known to harbor planetary companions, and the physical properties of these host stars provide an important link between the planets detected today and the circumstellar environments from which they formed long ago. Determining the relationship between stellar mass and planet occurrence provides an important test of the core accretion model of planet formation, which predicts the fraction of stars with planets increases with stellar mass. To measure the occurrence rate of planets as a function of mass, the I am conducting precision Doppler survey of intermediate- mass (1.3 to 1.9 Msun) subgiant stars at Lick and Keck Observatories, in conjunction with the California and Carnegie Planet Search. I will discuss how subgiants are ideal proxies of A and F type main-sequence stars in Doppler-based planet searches. I'll present the latest planet detections from my sample, including an eccentric "hot Jupiter," and several planets orbiting "retired" A stars.