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 recently announced super-Earths and Neptune-mass planets from the Eta-Earth Survey, including the 9 Earth mass planet HD 7924b and others. These low-mass planets are extraordinarily valuable in their own right, as targets for transit and other follow-up studies, and as windows into the mechanisms of planet formation. 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 (Mstar < 0.8 solar masses), in contrast to the trend seen in higher mass planets. The survey observations are nearly complete, allowing us to place initial constraints on the population of super-Earth and Neptune-mass planets, and, using planet-formation theory, to extrapolate to the fraction of Earth-mass planets and 1 year orbits.
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010