Resonance capture and the formation of the outer planets

• Published in: Monthly notices of the Royal Astronomical Society Vol. 270; no. 1; pp. 21 - 34
• Main Authors: Beaugé, C., Aarseth, S. J., Ferraz-Mello, S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford University Press 01-09-1994
• Subjects: accretion; accretion discs; celestial mechanics; methods: numerical; planets and satellites: general; Solar system: formation; stellar dynamics
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/270.1.21

In this paper we study a possible process for the formation of the outer planets, in which resonance capture induces the accretion of the planetary cores near exterior mean-motion commensurabilities of existing bodies. A two-dimensional N-body simulation is performed to test this hypothesis in the case of Saturn. Initial conditions consist of a swarm of 1000 equal-mass planetesimals distributed over a planar ring with extrema at 6.5 and 15 au. All bodies are originally in circular orbits. For the dynamical evolution of the population, the following interactions are considered: mutual gravitation between the bodies, physical collisions, gravitational perturbations from an existing Jupiter (present mass and orbit) and gas drag. The simulation is followed until a single body remains. The results show a single planetary core in a stable orbit with elements a = 9.78 au and e = 0.086, well in accord with the presentday Saturn. We also discuss the possible extension of these results to the formation of the other major planets.