Joint Astrophysics Colloquium

The Role of Tides for Extrasolar Planets and Their Satellites

Phil Arras

University of Virginia

Many extrasolar planets are so close to their parent star that tides may produce important effects, such as circularization of the orbit, and decay of the orbit toward the star. After reviewing the observational motivation for such tidal evolution, I'll discuss models for the structure and thermal evolution of strongly irradiated gas giants, whose large observed radii require a powerful “anomalous” heat source. I'll discuss possible mechanisms for tides to produce such steady state heating. Lastly, I'll discuss the possibility that close-in planets can have long-lived moons.