摘要：Context. The consistency of planet formation models suffers from the
disconnection between the regime of small and large bodies. This is primarily caused by
so-called growth barriers: the direct growth of larger bodies is halted at
centimetre-sized objects and particular conditions are required for the formation of
larger, gravitationally bound planetesimals.
Aims. We aim to connect models of dust evolution and planetesimal
formation to identify regions of protoplanetary discs that are favourable for the
formation of kilometre-sized bodies and the first planetary embryos.
Methods. We combine semi-analytical models of viscous protoplanetary
disc evolution, dust growth and drift including backreaction of the dust particles on the
gas, and planetesimal formation via the streaming instability into one numerical code. We
investigate how planetesimal formation is affected by the mass of the protoplanetary disc,
its initial dust content, and the stickiness of dust aggregates.
Results. We find that the dust growth and drift leads to a global
redistribution of solids. The pile-up of pebbles in the inner disc provides local
conditions where the streaming instability is effective. Planetesimals form in an annulus
with its inner edge lying between 0.3 AU and 1 AU and its width ranging from 0.3 AU to 3
AU. The resulting surface density of planetesimals follows a radial profile that is much
steeper than the initial disc profile. These results support formation of terrestrial
planets in the solar system from a narrow annulus of planetesimals, which reproduces their
peculiar mass ratios.
关键词：accretion, accretion disks;circumstellar matter;protoplanetary disks;planets and satellites: formation;methods: numerical
