Revised radii of KIC stars & planets using Gaia DR2

We report revised radii of 177911 Kepler stars derived by combining parallaxes from the Gaia Data Release 2 with the DR25 Kepler Stellar Properties Catalog. The median radius precision is ~8%, a typical improvement by a factor of 4-5 over previous estimates for typical Kepler stars.

We find that ~67% (~120000) of all Kepler targets are main-sequence stars, ~21% (~37000) are subgiants, and ~12% (~21000) are red giants, demonstrating that subgiant contamination is less severe than some previous estimates and that Kepler targets are mostly main-sequence stars. Using the revised stellar radii, we recalculate the radii for 2123 confirmed and 1922 candidate exoplanets. We confirm the presence of a gap in the radius distribution of small, close-in planets, but find that the gap is mostly limited to incident fluxes >200F_{Earth}_, and its location may be at a slightly larger radius (closer to ~2R_{Earth}_) when compared to previous results.