Ken RICE : Institute for Astronomy, University of Edinburgh
Planetesimal formation in self-gravitating protoplanetary discs
An unresolved issue in gaseous planet formation is how kilometer-sized planetesimals form from, initially, micron-sized dust grains. The drag force between the gas and the solid particles will tend to cause the solid particles to lose angular momentum and to spiral into the central star. This inward migration rate can become extremely large, creating a problem for planetesimal formation, since these particles may migrate into the central star before becoming large enough to decouple from the disc gas. In a quasi-steady, self-gravitating disc, however, solid particles will tend to migrate towards the centre of the spiral structures, rather than inwards towards the central star. We show here that the solid particle densities may be enhanced by an order of magnitude or more and that the densities achieved may lead to planetesimal formation through gravitational collapse. This may provide a process for the formation of planetesimals that later coagulate to form the cores of giant planets.Last modified: Sun Jul 9 18:13:46 2006