Dr. Adrian Barker
DAMTP, University of Cambridge
Over 1000 planets have been discovered orbiting stars other than the Sun. Many of these orbit their stars very closely, with orbital periods as short as one Earth day. Observations indicate that the tidal gravitational interaction between a close-in planet and its host star can have important effects on the planetary orbit. In particular, it is thought that the dissipation of tidally excited flows inside short-period planets can explain why their orbits tend to be circular, in comparison to those that orbit more distantly, which have a wide range of orbital eccentricities. I will first introduce the subject area, before presenting some recent work on the nonlinear evolution of tidally excited flows in rotating planets, which aims to understand the mechanisms of tidal dissipation, and ultimately to explain these astrophysical observations.