Constraining Planetary Formation with Gravity Darkening on Variable Stars

Observations of exoplanets over the past twenty years have revealed a diverse arrangement of planetary systems. This diverse arrangement, consisting of planets orbiting their host stars in all manner of orbital configurations, poses problems for traditionally accepted models of planetary formation and evolution. In particular, these models predict that planets should orbit their host stars in roughly the same plane as the star’s equator, however this is not the case for all observed planetary systems. Different models have been proposed to explain this discrepancy. We set out to constrain these models for planets orbiting high-mass stars by measuring their misalignment from their star’s equator. Such measurements help constrain proposed mechanisms of misalignment by offering a glimpse into the planet’s formation history. We measure a planet’s misalignment using two independent techniques. The first depends on a stellar pole to equator brightness gradient, referred to as gravity darkening, that arises due to a star’s rotation. The second relies on analyzing brightness variations inherent in so called variable stars. We apply our technique to Kepler Object of Interest 972, a planetary candidate orbiting a variable star and discuss our preliminary results