RV standard deviation in the M2K survey

Our analysis is based on the presumption that the planet populations around the two sets of stars are the same. The model can reproduce the observed distribution of radial velocity variation over a range of parameter values, but, for the expected level of Doppler systematic error, the highest Kolmogorov-Smirnov probabilities occur for a power-law index {alpha}{approx}4, indicating that rocky-metal planets dominate the planet population in this size range.

A single population of gas-rich, low-density planets with {alpha}=2 is ruled out unless our Doppler errors are >=5m/s, i.e., much larger than expected based on observations and stellar chromospheric emission. If small planets are a mix of {gamma} rocky planets ({alpha}=3.85) and 1-{gamma} gas-rich planets ({alpha}=2), then {gamma}>0.5 unless Doppler errors are >=4m/s. Our comparison also suggests that Kepler's detection efficiency relative to ideal calculations is less than unity.