Super-Earths and Neptunes from the Eta-Earth Survey
Andrew Howard (UC Berkeley)
Monday 5th April 2010, 12:00pm
Pratt conference room, 60 Garden Street
The NASA-UC Eta-Earth Survey by the California Planet Search (CPS) group is a systematic search for low-mass planets (~3-30 Earth masses) orbiting the nearest 230 GKM stars suitable for high-precision Doppler observations at Keck Observatory. These 1 m/s measurements of a well-defined sample of nearby stars will provide one of the first estimates of the fraction of stars with Earth-like planets. The talk will describe recent detections of super-Earths and Neptune-mass planets from the Eta-Earth Survey, including the 4 Earth mass planet HD156668b and the 9 Earth mass planet HD 7924b. In addition to individual detections, I will discuss limits on the occurance of low-mass planets with periods of less than 20 days. Low mass planets show several emerging trends in their orbital parameters and in the characteristics of their host stars. For example, super-Earth and Neptune-mass planets preferentially orbit stars with lower mass (M_star < 0.8 solar masses).