The Formation of Planetesimals
1973; IOP Publishing; Volume: 183; Linguagem: Inglês
10.1086/152291
ISSN1538-4357
AutoresPeter Goldreich, William R. Ward,
Tópico(s)Astronomy and Astrophysical Research
Resumoview Abstract Citations (891) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Formation of Planetesimals Goldreich, Peter ; Ward, William R. Abstract Four stages in the accretion of planetesimals are described. The initial stage is the condensation of dust particles from the gaseous solar nebula as it cools. These dust particles settle into a thin disk which is gravitationally unstable. A first generation of planetesimals, whose radii range up to 10-1 km, form from the dust disk by direct gravitational collapse to solid densities on a time scale of the order of 1 year. The resulting disk, composed of first-generation planetesimals, is still gravitationally unstable, and the planetesimals are grouped into clusters containing approximately 10 members. The contraction of these clusters is controlled by the rate at which gas drag damps their internal rotational and random kinetic energies. On a time scale of a few thousand years, the clusters contract to form a second generation of planetesimals having radii of the order of 5 km. Further coalescence of planetesimals proceeds by direct collisions which seem capable of producing growth at a rate of the order of 15 cm per year at 1 a.u. The final stage of accretion during which planet-sized objects form is not considered here. Subject headings: planets - solar system Publication: The Astrophysical Journal Pub Date: August 1973 DOI: 10.1086/152291 Bibcode: 1973ApJ...183.1051G full text sources ADS |
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