Forming planetesimals in vortices: The dynamics of heavy
     impurities in a rotating, flat gaseous disk.

     P. Tanga and A. Provenzale (Istituto di Cosmogeofisica del
                                       CNR - Torino, Italy)
     A. Babiano (LMD, Paris, France)
     B. Dubrulle (SAp, Saclay, France)



  At large scales, a rotating flat accretion disk is characterized by a
  quasi 2-Dimensional turbulence, due to the anisotropy created by the
  Coriolis force. As a result, energy dissipation at large scales is
  inhibited, with creation of long-lived vortices.
  The transport of heavy particles in a simple analitical model of this
  turbulent configuration is studied, and a segregation effect of heavy
  particles inside coherent structures is found. The implications of
  this result on planet formation is discussed.