Planetesimal formation via the streaming instability with multiple grain sizes

ABSTRACT Kilometre-sized planetesimals form from pebbles of a range of sizes. We present the first simulations of the streaming instability (SI) that begin with a realistic, peaked size distribution, as expected from grain growth predictions. Our 3D numerical simulations directly form planetesimals via the gravitational collapse of pebble clouds. Models with multiple grain sizes show spatially distinct dust populations. The smallest grains in …