Apsidal Behavior Among Planetary Orbits: Testing the Planet-Planet Scattering Model

Abstract

Planets in extrasolar systems tend to interact such that their orbits lie near a boundary between apsidal libration and circulation, a "separatrix", with one eccentricity periodically reaching near-zero. One explanation, applied to the Upsilon Andromedae system, assumed three original planets on circular orbits. One is ejected, leaving the other two with near-separatrix behavior. We test that model by integrating hundreds of hypothetical, unstable planetary systems that eject a planet. We find that the probability that the remaining planets exhibit near-separatrix motion is small (< 5% compared with nearly 50% of observed systems). Moreover, while observed librating systems are evenly divided between aligned and anti-aligned pericenter longitudes, the scattering model strongly favors alignment. Alternative scattering theories are proposed, which may provide a more satisfactory fit with observed systems.

10 pages, 2 figures, accepted to ApJ Letters

References in corpus (8)

• Catalog of Nearby Exoplanets
• The origin of planetary impactors in the inner solar system
• Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars
• Stability Limits in Extra-solar Planetary Systems
• Evidence for Planet-Planet Scattering in Upsilon Andromedae
• The HARPS search for southern extra-solar planets. IX. mu Ara, a system with four planets
• The (In)Stability of Planetary Systems
• Behavior of Apsidal Orientations in Planetary Systems

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• Origin and Dynamics of the Mutually Inclined Orbits of Upsilon Andromedae c and d
• The 3-dimensional architecture of the Upsilon Andromedae planetary system
• Detection of Water Vapor in the Thermal Spectrum of the Non-Transiting Hot Jupiter upsilon Andromedae b
• Secular transport during disk dispersal: the case of Kepler-419
• Characterizing Multi-planet Systems with Classical Secular Theory
• Secular Behavior of Exoplanets: Self-Consistency and Comparisons with the Planet-Planet Scattering Hypothesis
• Extrasolar Planet Interactions