High-accuracy statistical simulation of planetary accretion: II. Comparison with N-body simulation

We have constructed an improved statistical method for the calculation of p lanetary accumulation using the currently standard model of terrestrial pla net formation and using the latest results of planetary dynamical theory, T he method is applicable for the range of masses in which velocity changes a re dominated by gravitational forces, mutual collisions, and gas drag. Calc ulations are reported both with and without nebular gas. This method has be en compared with N-body simulations, and the results of the two calculation s are in agreement, As in earlier calculations, the growth of bodies in thi s mass range and at 1 AU occurs on a similar to 10(5) year time scale and i s characterized by the evolution of an initially continuous mass distributi on into a bimodal distribution, the high mass end of which consists of runa way bodies in the size range of similar to 10(26) g, In this general way, t hese results are in agreement with those reported earlier (e.g., Wetherill and Stewart 1993, Icarus 106, 190-209), but significant differences are als o found as a result of the greater precision of the collision rate and the velocity evolution rate of planetesimals used in the present work. (C) 2001 Academic Press.