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E.J. Rivera (SUNY, Stony Brook; NASA Ames), J.J. Lissauer (NASA Ames)
We present results of numerical orbital integrations designed to test the stability of the three planets detected in orbit around \upsilon Andromedae and possible smaller bodies orbiting in the system which have not yet been discovered. We find that some configurations consistent with the data reported by in the original version of Butler et al. (1999) are stable for at least 109 years, whereas in other configurations planets can be ejected into interstellar space in less than 105 years. The typical path to instability involves the outer planet exciting the eccentricity of the middle planet's orbit to such high values that it ventures close to the inner planet. In some stable systems a secular resonance between the outer two planets prevents close approaches between them by aligning their longitudes of periastron. In relatively stable systems, test particles can survive for long times between the inner and middle planets as well as several AU exterior to the outer planet, but we could find no stable orbits between the middle and outer planets.
This research was supported in part by NASA's OSSRP grant NAG5-4640.
The author(s) of this abstract have provided an email address for comments about the abstract: rivera@epimethius.arc.nasa.gov