Frederic Masset - November 17, 2016

Impact of heat release on the orbital elements of forming protoplanets

I will in a first part present some basic concepts of planet-disk interactions.
In particular I will present how these interactions trigger a drift of the
planetary semi-major axis (called planetary migration) and how they usually
dampen the eccentricity on a short time scale. I will then consider embryos or
protoplanets heated by planetesimal bombardment. The heat released in the
ambient gas alters the nearby density distribution, and ultimately the tidal
force experienced by the planet. I will show how this effect plays in favor of
outwards migration, and may help to account for the formation of critical mass
cores of giant planets at sizable distances of the star. Finally, after
examining the effect of heat release in the simpler context of dynamical
friction in a homogeneous medium at rest, I will make some predictions about the
eccentricities and inclinations of embryos and protoplanets embedded in gaseous,
opaque protoplanetary disks.