Astronomy Colloquium

The unexpected diversity of observed extrasolar planetary systems has posed new challenges to our classical understanding of planetary formation. Many of the puzzles can be explained by an unseen stellar companion. In this talk, I will first discuss the Lidov-Kozai mechanism, which has important applications to planetary systems perturbed by a farther companion. In particular, we find that the perturbation from the stellar companion can flip the inner orbit by 180 degrees, and produce a counter orbiting hot Jupiter. Moreover, I will discuss the origin of circumbinary planets, which are planets orbiting around a stellar binary, based on architectural properties of the transiting sample studied by a statistical approach.