Scattering Outcomes of Close-in Planets: Constraints on Planet Migration

摘要: Many exoplanets in close-in orbits are observed to have relatively high eccentricities and large stellar obliquities. We explore the possibility that these result from planet-planet scattering by studying dynamical outcomes a number of orbit integrations systems with two three gas-giant planets (0.05 AU < 0.15 AU). find at orbital separations, unstable starting low mutual inclinations (e ≲ 0.1, i 0.1) generally lead collisions which collision product is planet on low-eccentricity, low-inclination orbit. This inconsistent observations. conclude eccentricity inclination excitation must precede migration into short-period orbits. constrains theories migration: semi-major axis shrink 1-2 orders magnitude without damping inclination.