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Measurement Of Spin-Orbit Misalignment And Nodal Precession For The Planet Around Pre-Main-Sequence Star Ptfo 8-8695 From Gravity Darkening, Jason W. Barnes, Julian C. Van Eyken, Brian K. Jackson, David R. Ciardi, Jonathan J. Fortney

Brian Jackson

PTFO 8-8695b represents the first transiting exoplanet candidate orbiting a pre-main-sequence star (van Eyken et al. 2012, ApJ, 755, 42). We find that the unusual lightcurve shapes of PTFO 8-8695 can be explained by transits of a planet across an oblate, gravity-darkened stellar disk. We develop a theoretical framework for understanding precession of a planetary orbit’s ascending node for the case when the stellar rotational angular momentum and the planetary orbital angular momentum are comparable in magnitude. We then implement those ideas to simultaneously and self-consistently fit two separate lightcurves observed in 2009 December and 2010 December. Our two self-consistent …