N ‐Body Simulation of Planetesimal Formation through Gravitational Instability of a Dust Layer

Abstract

We performed N-body simulations of a dust layer without a gas component and examined the formation process of planetesimals. We found that the formation process of planetesimals can be divided into three stages: the formation of nonaxisymmetric wakelike structures, the creation of aggregates, and the collisional growth of the aggregates. Finally, a few large aggregates and many small aggregates are formed. The mass of the largest aggregate is larger than the mass predicted by the linear perturbation theory. We examined the dependence of system parameters on the planetesimal formation. We found that the mass of the largest aggregates increases as the size of the computational domain increases. However, the ratio of the aggregate mass to the total mass Maggr/Mtotal is almost constant, 0.8-0.9. The mass of the largest aggregate increases with the optical depth and the Hill radius of particles.