Frédéric Masset
planetary embryos should be flushed onto their central star in less than it takes to build a giant planet, posing the question of why many systems harbor giant planets at sizable distances of their star.
Recent results in the theories of migration of low mass planets have nevertheless changed this picture. In particular, the coorbital region and the torque that it exerts on the planet, named the corotation torque, have been extensively revisited, and shown to be very sensitive to the equation of state of the gas. After a general introduction on planetary migration, I will present in detail the dynamics of the corotation region, and I will show how the baroclinicity of the gas introduces an important new term in the corotation torque, that is able to stall or reverse planetary migration, with important consequences on the theories of formation of planetary systems.
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris