Planet-Planet Scattering in Planetesimal Disks
Venue
Astrophysical Journal Letters, vol. 699 (2009), L88-L92
Publication Year
2009
Authors
Sean N. Raymond, Philip J. Armitage, Noel Gorelick
BibTeX
Abstract
We study the final architecture of planetary systems that evolve under the combined
effects of planet-planet and planetesimal scattering. Using N-body simulations we
investigate the dynamics of marginally unstable systems of gas and ice giants both
in isolation and when the planets form interior to a planetesimal belt. The
unstable isolated systems evolve under planet-planet scattering to yield an
eccentricity distribution that matches that observed for extrasolar planets. When
planetesimals are included the outcome depends upon the total mass of the planets.
For M tot gsim 1 MJ the final eccentricity distribution remains broad, whereas for
M tot lsim 1 MJ a combination of divergent orbital evolution and recircularization
of scattered planets results in a preponderance of nearly circular final orbits. We
also study the fate of marginally stable multiple planet systems in the presence of
planetesimal disks, and find that for high planet masses the majority of such
systems evolve into resonance. A significant fraction leads to resonant chains that
are planetary analogs of Jupiter's Galilean satellites. We predict that a
transition from eccentric to near-circular orbits will be observed once extrasolar
planet surveys detect sub-Jovian mass planets at orbital radii of a sime 5-10 AU.
