On the Stability of Test Particles in Extrasolar Multiple Planet Systems

We present results of extensive numerical studies of the stability of non-interacting particles in the planetary systems of stars Upsilon Andromedae, GJ 876, 47 UMa, and 55 Cancri. We discuss the possibility of the existence of islands of stability and/or instability at different regions in these multi-body systems, and their probable correspondence to certain mean-motion resonances. The results of our study may be applied to questions concerning the stability of terrestrial planets in these systems and also the trapping of particles in resonances with the planets.