Can a Migrating Gas Giant Planet Retain a System of Moons?

At the present time, approximately forty extrasolar planets have been discovered by detecting periodic radial velocity variations of the parent star. Instrument sensitivity and time limitations constrain these detections to high mass planets with short period orbits. In addition, recent observations of the planet orbiting HD209458 passing in front of its parent star reveal that these extrasolar planets are indeed gas giants. Currently accepted ideas of solar system formation do not permit gas giant planets to form so close to their parent star. Instead, it is believed that these planets formed further out, and then migrated inward through gravitational interactions with a nebular disk of gas and solid material. We examine the question of what would happen to a giant planet's system of moons during such a migration. We assume that the planet has a fully formed system of moons and that it migrates through a swarm of protoplanets. We use a gravitational N-body simulation to integrate the orbits, close encounters, and collisions of the giant planet, moons, and protoplanet swarm. Preliminary results indicate that if such a migration occurs, it is unlikely that the system of moons will survive.