Tilting Planets During Planet Scattering

Abstract

Observational constraints on planet spin-axis has recently become possible, and revealed a system that favors a large spin-axis misalignment, a low stellar spin-orbit misalignment and a high eccentricity. To explain the origin of such systems, we propose a mechanism that could tilt the planet spin-axis during planet-planet scattering, which are natural outcomes of in-situ formation and disk migration. Specifically, we show that spin-orbit resonances could occur for a short time period during the scattering processes, and excite the misalignment of the planet spin-axis. This typically leads to planets with large spin-misalignment and a wide range of eccentricities and inclinations.