Forming planetesimals in vortices

In this work we explore the possibility that large-scale, quasi-two-dimensional vortices on the solar nebula act as trapping regions for dust particles, We show that large-scale vortices may be naturally generated in a differentially rotating solar nebula, and we discuss a simple self-similar solution for the vortex pattern, Numerical simulations of the transport of dust in the presence of vortices on the nebula indicate that for a Rossby number less than one the Coriolis force pushes the heavy particles into the cores of anticyclonic (retrograde) vortices. Here the concentration of dust grains becomes much larger than outside in a few periods of revolution of the disk, The cares of anticyclonic vortices are thus identified as candidate regions for rapid planetesimal formation. (C) 1996 Academic Press, Inc.