Data di Pubblicazione:
2009
Citazione:
Limits on the location of planetesimal formation in self-gravitating protostellar discs / C. J. Clarke, G. Lodato. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 398:1(2009 Sep 01), pp. L6-L10.
Abstract:
In this Letter, we show that if planetesimals form in spiral features in self-gravitating discs, as
previously suggested by the idealized simulations of Rice et al., then in realistic protostellar
discs, this process will be restricted to the outer regions of the disc (i.e. at radii in excess of
several tens of au). This restriction relates to the requirement that dust has to be concentrated
in spiral features on a time-scale that is less than the (roughly dynamical) lifetime of such
features, and that such rapid accumulation requires spiral features whose fractional amplitude
is not much less than unity. This in turn requires that the cooling time-scale of the gas is
relatively short, which restricts the process to the outer disc. We point out that the efficient
conversion of a large fraction of the primordial dust in the disc into planetesimals could rescue
this material from the well-known problem of rapid inwardmigration at an approximate metresize
scale and that in principle the collisional evolution of these objects could help to resupply
small dust to the protostellar disc. We also point out the possible implications of this scenario
for the location of planetesimal belts inferred in debris discs around main sequence stars, but
stress that further dynamical studies are required in order to establish whether the disc retains
a memory of the initial site of planetesimal creation.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
accretion, accretion discs; hydrodynamics; instabilities; planetary systems: formation
Elenco autori:
C. J. Clarke, G. Lodato
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