The formation and extent of the solar system comet cloud

Abstract

The authors present the results of numerical simulations of the origin and evolution of the solar system comet cloud. They assume that comets formed in the outer planetary region and that their orbits evolved to their current state through planetary perturbations, stellar encounters, and the galactic tide. The evolution is followed using a hybrid integration scheme which directly integrates the regularized equations of motion for cometary orbits with large semimajor axes, while solving an energy-diffusion equation for more tightly bound orbits. Stellar encounters are introduced via a Monte Carlo approach using the impulse approximation. The results of the simulations are discussed in detail.