Planetesimal accretion in planetesimal rings
Speaker: Yuki Kambara
Abstract:
In the standard planet formation scenario, planetesimals have been assumed to be smoothly distributed in the radial direction except for the snowline. Recently, however, simulations of gas and dust evolution have shown that planetesimals form only in radially limited locations, such as gas pressure bumps and snowlines, and are concentrated in ring-like regions.
The evolution process of planetesimals distributed in a ring is crucial to understanding planet formation theory. However, the evolution of planetesimal rings has not been studied in detail. In this work, we investigate the evolution of planetesimal rings using N-body simulations. We systematically change the initial width and the total mass of planetesimal rings and investigate the dependence of protoplanet properties on the initial conditions. In all simulations, protoplanets undergo oligarchic growth while ring width expands due to scattering by protoplanets. In planetesimal rings, massive protoplanets tend to be formed around the ring center, while protoplanets far from the center of rings are less massive. Scaled orbital separation depends neither on the initial ring width nor the total mass and is consistent with the estimate in the oligarchic growth model. The width of the expanded planetesimal ring does not depend on the initial ring width but on the total ring mass. The maximum mass of protoplanets depends strongly on the total ring mass and weakly on the initial ring width.