Planetesimal accretion in planetesimal rings

In the standard scenario of planet formation, planetesimals form throughout the protoplanetary disk and are 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 the limited locations, such as gas pressure bumps and snowlines, and that planetesimals are concentrated in ring-like regions. Simulations starting from protoplanets arranged in a narrow annulus succesfully reproduced the mass distribution of terrestrial planets in the solar system. In addition, the existence of ring structures in the planet formation process has been supported by a number of results. When planetesimals are distributed in a narrow ring, their evolution would change from the standard scenario, and the distribution of protoplanets and planets that form from them would also change. However, the evolution of planetesimal rings has not been studied in detail. Therefore, we investigate the evolution of planetesimal rings using N-body simulations. In narrower and denser rings, planetesimals grow faster, and the fast growth causes fast expansion of the ring. As a result, the distribution of planetesimals does not depend on the initial width of the ring after runaway growth stage. In the presentation, we will show the dependence of the mass and orbital distribution of protoplanets on the ring width and surface density, and discuss the effects of different planetesimal distributions on the protoplanet formation.