Peter Plavchan, Christopher Bilinski, Thayne Currie
The recent announcement of 2300+ candidate transiting exoplanets (KOIs) orbiting ~1800 host stars discovered with the Kepler mission enables a plethora of ensemble analysis of the architecture and properties of exoplanetary systems. We use the transit durations to probe the ensemble validity of stellar parameters for Kepler candidate host stars. Our analysis shows that the new stellar parameters are improved over the second release of KOIs. However, a systematic over-estimate of the ensemble K&M dwarf radii remains, which affects the KOI exoplanet radii inferred from transit depths. We also compare the distribution of observed transit durations to a modeled distribution of transit durations derived from the known eccentricity distribution of radial velocity (RV) discovered exoplanets. In agreement with previous work, the transit durations modeled from the RV eccentricity distribution are well described by a normal distribution. However, we find that the Kepler and RV distributions differ at a statistically significant level, even after accounting for the transit probability as a function of the eccentricity, inclination and periastron angle. There is clearly an over-abundance of KOIs with transit durations that are too long relative to analytic models, given that an eccentric transiting planet has a higher probability of transiting near periastron. Some of these KOIs must be attributable to errors in the host stellar parameters or alternatively are false-positives.
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http://arxiv.org/abs/1203.1887
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