Formation of terrestrial planets in eccentric and inclined giant planet systems

Abstract

Evidence of mutually inclined planetary orbits has been reported for giant planets these last years. Here we aim to study the impact of eccentric and inclined massive giant planets on the terrestrial planet formation process, and investigate whether it can possibly lead to the existence of inclined terrestrial planets. We have performed 126 simulations of the late-stage planetary accretion in eccentric and inclined giant planet systems. The physical and orbital parameters of the giant planet systems result from n-body simulations of three giant planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. Fourteen two- and three-planet configurations have been selected, with diversified masses, semi-major axes (resonant configurations or not), eccentricities and inclinations (including coplanar systems) at the dispersal of the gas disc. We have then followed the gravitational interactions of these systems with an inner disc of planetesimals and embryos (9 runs per system), studying in detail the final configurations of the formed terrestrial planets. While coplanar giant systems harbour several terrestrial planets, generally as massive as the Earth and mainly on low eccentric and low inclined orbits, terrestrial planets formed in systems with mutually inclined giant planets are usually fewer, less massive (<0.5 M_{\Earth}) and with larger eccentricities and inclinations. This work shows that terrestrial planets can form on stable inclined orbits through the classical accretion theory, even in coplanar giant planet systems emerging from the disc phase.