Characterizing the Cool KOIs VIII. Parameters of the Planets Orbiting Kepler's Coolest Dwarfs

Abstract

The coolest dwarf stars targeted by the Kepler Mission constitute a relatively small but scientifically valuable subset of the Kepler target stars, and provide a high-fidelity and nearby sample of transiting planetary systems. Using archival Kepler data spanning the entire primary mission we perform a uniform analysis to extract, confirm and characterize the transit signals discovered by the Kepler pipeline toward M-type dwarf stars. We recover all but two of the signals reported in a recent listing from the Exoplanet Archive resulting in 165 planet candidates associated with a sample of 106 low-mass stars. We fitted the observed light curves to transit models using Markov Chain Monte Carlo and we have made the posterior samples publicly available to facilitate further studies. We fitted empirical transit times to individual transit signals with significantly non-linear ephemerides for accurate recovery of transit parameters and measuring precise transit timing variations. We also provide the physical parameters for the stellar sample, including new measurements of stellar rotation, allowing the conversion of transit parameters into planet radii and orbital parameters.