Self-consistent N-body simulation of planetesimal-driven migration. I. The trajectories of single planets in the uniform background.

This article focuses on investigating planetesimal-driven migration (PDM) as a mechanism of planetary migration within protoplanetary disks, using high-resolution, self-consistent N-body simulations that incorporate gravitational interactions among planetesimals, aerodynamic gas drag, and Type I migration. The study demonstrates that even small protoplanets can undergo significant radial migration through PDM, including outward migration that may counteract inward Type I migration, challenging previous assumptions about the necessary mass ratios for effective PDM. The simulations reveal that the monotonicity of PDM increases with the number of planetesimals due to reduced two-body relaxation effects, and that outward migration via PDM could play a role in the formation and radial distribution of planetary cores, including those of outer planets. These findings refine existing PDM criteria and suggest that planetary embryos can actively migrate during early growth phases, with implications for planetary formation theories.