Robo-AO Kepler Planetary Candidate Survey III: Adaptive Optics Imaging of 1629 Kepler Exoplanet Candidate Host Stars


Abstract in English

The Robo-AO textit{Kepler} Planetary Candidate Survey is observing every textit{Kepler} planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. We present in this paper the results of our search for stars nearby 1629 textit{Kepler} planet candidate hosts. With survey sensitivity to objects as close as $sim$0.15 and magnitude differences $Delta$m$le$6, we find 223 stars in the vicinity of 206 target KOIs; 209 of these nearby stars have not previously been imaged in high resolution. We measure an overall nearby-star probability for textit{Kepler} planet candidates of 12.6%$pm$0.9% at separations between 0.15 and 4.0. Particularly interesting KOI systems are discussed, including 23 stars with detected companions which host rocky, habitable zone candidates, and five new candidate planet-hosting quadruple star systems. We explore the broad correlations between planetary systems and stellar binarity using the combined dataset of Baranec et al. (2016) and this paper. Our previous 2$sigma$ result of a low binary fraction of KOIs hosting close-in giant planets is less apparent in this larger dataset. We also find a significant correlation between binary fraction and KOI number, suggesting possible variation between early and late textit{Kepler} data releases.

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