MODELING THE DIVERSITY OF OUTER PLANETARY SYSTEMS

In order to better understand the range of dynamically long-lived gian t planet systems, we present the results of a set of bottom-up numeric al simulations designed to generate plausible giant planet systems fro m a large number of planetary embryos. Our simulations produced system s that are stable for at least a billion years and that exhibit a wide range of characteristics. Some of these systems are reminiscent of th e outer solar system. The number of planets ranged from one to seven. Many systems contained only Uranus-mass objects. We constructed system s that were more compact than the outer solar system and systems that were much sparser, with planets on very eccentric orbits. Perhaps most surprisingly, some of the systems that we constructed were stable for at least a billion years despite undergoing macroscopic orbital chang es on much shorter timescales.