SETI bioastro: Planetesimal formation via fragmentation in self-gravitating protoplanetary disc

From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Jul 14 2006 - 12:08:24 PDT

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    Astrophysics, abstract
    astro-ph/0607268

    From: W. K. M. Rice [view email]

    Date: Wed, 12 Jul 2006 20:01:04 GMT (433kb)

    Planetesimal formation via fragmentation in self-gravitating protoplanetary
    discs

    Authors: W.K.M. Rice, G. Lodato, J.E. Pringle, P.J. Armitage, I.A. Bonnell

    Comments: 5 pages, Accepted for publication in MNRAS

    An unsolved issue in the standard core accretion model for gaseous planet
    formation is how kilometre-sized planetesimals form from, initially,
    micron-sized dust grains. Solid growth beyond metre sizes can be difficult
    both because the sticking efficiency becomes very small, and because these
    particles should rapidly migrate into the central star. We consider here how
    metre-sized particles evolve in self-gravitating accretion discs using
    simulations in which the gravitational influence of the solid particles is
    also included. Metre-sized particles become strongly concentrated in the
    spiral structures present in the disc and, if the solid to gas density ratio
    is sufficiently high, can fragment due to their own self-gravity to form
    planetesimals directly. This result suggests that planetesimal formation may
    occur very early in the star formation process while discs are still massive
    enough to be self-gravitating. The dependence of this process on the surface
    density of the solids is also consistent with the observation that
    extrasolar planets are preferentially found around high metallicity stars.

    http://arxiv.org/abs/astro-ph/0607268


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