Metallicities of KIC stars without planets

The giant planet metallicity correlation has now been widely accepted, but questions remain as to whether the metallicity correlation extends to the small terrestrial-sized planets. Here, we report metallicities for a sample of 518 stars in the Kepler field that have no detected transiting planets and compare their metallicity distribution to a sample of stars that hosts small planets (Rp<1.7R_{Earth}_).

Importantly, both samples have been analyzed in a homogeneous manner using the same set of tools (Stellar Parameters Classification tool). We find the average metallicity of the sample of stars without detected transiting planets to be [m/H]_SNTP,dwarf_=-0.02+/-0.02dex and the sample of stars hosting small planets to be [m/H]_STP_=-0.02+/-0.02dex. The average metallicities of the two samples are indistinguishable within the uncertainties, and the two-sample Kolmogorov-Smirnov test yields a p-value of 0.68 (0.41{sigma}), indicating a failure to reject the null hypothesis that the two samples are drawn from the same parent population.