2014ApJ...786..131A

We fit the Kepler photometric light curve of the KOI-368 system using an oblate, gravity-darkened stellar model in order to constrain its spin-orbit alignment. We find that the system is relatively well-aligned with a sky-projected spin-orbit alignment of λ = 10°±2°, a stellar obliquity of ψ = 3°±7°, and a true spin-orbit alignment of φ = 11°±3°. Although our measurement differs significantly from zero, the low value for φ is consistent with spin-orbit alignment. We also measure various transit parameters of the KOI-368 system: R_KOI–368= 2.28±0.02 R_☉, R_p= 1.83±0.02 R_jup, and i = 89.°221±0.°013. This work shows that our gravity-darkened model can constrain long-period, well-aligned planets and M-class stars orbiting fast-rotators, allowing for measurement of a new subcategory of transiting bodies.