Vol. 542
In section 10. Planets and planetary systems

Formation and long-term evolution of 3D vortices in protoplanetary discs

by H. Meheut, R. Keppens, F. Casse, and W. Benz, A&A 542, A9

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It has long been suggested that vortices may be the key for planetesimal formation in protoplanetary disks because of their ability to trap and concentrate solids. However, although vortices are known to be stable in two-dimensional situations, it has long been a conjecture only that they can survive for sufficiently long timescales in protoplanetary disks, where three-dimensional effects become important. Meheut et al. used an adaptive mesh in their new hydrodynamical simulations to show that when a density bump is created in the disk (e.g. through the ice line), Rossby wave instabilities develop and form vortices that last for tens of orbital times (~a hundred years or more at 3 Astronomical Units) before decaying. The presence of vortices could therefore play a major role in planetesimal formation, and in turn for planet formation.