Abstract

The obliquity of a star, or the angle between its spin axis and the orbit normal of its companion planets, provides a unique constraint on that system’s evolutionary history. In contrast with the solar system, where the Sun’s equator is nearly aligned with its companion planets, many hot Jupiter systems have been discovered with large stellar obliquities, hosting planets on polar or retrograde orbits. I will demonstrate that the observed stellar obliquity distribution, combined with tidal dissipation from star-planet interactions, points toward high-eccentricity migration as a key hot Jupiter formation mechanism. I will also present the first results from the Stellar Obliquities in Long-period Exoplanet Systems (SOLES) survey, which is extending the sample of stellar obliquity measurements to include systems with wide-orbiting planets that are more representative of the primordial obliquity distribution. Combining these results with additional constraints from TTV , RV, and transit surveys, I will conclude with a new paradigm for hot and warm Jupiter formation.