Short-term collisional evolution of a disc perturbed by a giant-planet embryo

¹ Université Paris 7 Denis Diderot, Service d'Astrophysique & CEA Saclay, France
² DESPA, Observatoire de Paris, 92195 Meudon Cedex Principal, France

Corresponding author: S. Charnoz, charnoz@discovery.saclay.cea.fr

Received: 26 December 2000
Accepted: 9 April 2001

Abstract

A simple numerical model has been developed to study the evolution of a disc of planetesimals under mutual inelastic collisions in the potential field of a central body and of an embedded giant-planet embryo. Masses for the latter range from 0.5 to 300 Earth masses. A mass of is typical of the solid-core model for the formation of giant planets. The initially cold disc consists of a few thousand particles. Those initially present between one and three Hill radii from the perturber's orbit are transferred to very eccentric orbits causing violent collisions throughout the disc. The perturbation propagates far from the perturber, like a heat transfer: a perturber orbiting at 5.2 a.u. heats up the disc from 2.3 to at least 11 a.u. from the central body in a few 10⁵ to 10⁶ years. Relative velocities are typically increased by a factor of 10 to 100. The extent of the heated region increases with the protoplanet's mass while the propagation timescale decreases. The resulting radial mixing has potential applications for the origin of the Asteroid Belt, in particular for the radial distribution of the asteroid's spectroscopic families.