Hot Jupiters (extrasolar gas giants in 1-5 day orbits) were first discovered 20 years ago, but their origin remains highly mysterious. Many hot Jupiter systems exhibit misalignment between the orbital axis of the planet and the spin axis of its host star. While this misalignment could be primordial in nature, a large fraction of hot Jupiters are found in systems with distant stellar companions, and thus could have undergone the so-called Lidov-Kozai oscillations and acquired their misalignment dynamically. 

Bio: Dong Lai is a Professor of Astrophysics at Cornell University. He received Ph.D. in physics from Cornell in 1994, and was a postdoctoral fellow at Caltech. He joined the faculty of the Astronomy Department at Cornell in 1997. His current research is in theoretical astrophysics, focusing on exoplanets, compact objects (neutron stars, black holes and white dwarfs), and astrophysical (fluid) dynamics in general.