George Zhou, Xu Chelsea Huang
We report the detection of asymmetry in the transit light curves of the 110-day period planet candidate KOI-368.01, orbiting a rapidly rotating A-dwarf. The significant distortion in the transit light curve is attributed to spin-orbit misalignment between the transiting companion and the gravity darkened host star. Our analysis was based on 11 Long Cadence and 2 Short Cadence transits of KOI-368.01 from the Kepler mission, as well as stellar parameters determined from our follow-up spectroscopic observation. We measure the true obliquity between the orbit normal and the stellar rotation axis to be 64 +11/-9 degrees. The orbital eccentricity is also constrained by the transit duration to be e=0.07 +0.18/-0.07. The long period, high obliquity, and potentially low eccentricity of KOI-368.01 makes it unique amongst systems with spin-orbit measurements, and appears to be incompatible with Kozai migration mechanisms involving wide stellar mass binaries.
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http://arxiv.org/abs/1307.2249
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