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Astron. Astrophys. 319, 1007-1019 (1997)

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Global evolution of solid matter in turbulent protoplanetary disks

II. Development of icy planetesimals

T.F. Stepinski 1 and P. Valageas 2

1 Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058, USA
2 Service de Physique Théorique, CEN Saclay, F-91191 Gif-sur-Yvette, France

Received 20 June 1996 / Accepted 12 September 1996


It is currently thought that planets around solar-type stars form by the accumulation of solid matter entrained in a gaseous protoplanetary disk. We model part of this process starting from small particles suspended in a gaseous disk, and ending up with most of the solid material aggregated into 1-10-km-sized planetesimals. The radial distribution of solid material circumnavigating a star in the form of the planetesimal swarm is the major result of this study, inasmuch as it provides insight into the large-scale character of the emerging planetary system. The model simultaneously keeps track of the evolution of gas and solid particles due to gas-solid coupling, coagulation, sedimentation, and evaporation/condensation. For simplicity, we concentrate on solids made up solely of water-ice. We have found that the radial distribution of mass locked into planetesimals is sensitive to initial conditions. Two illustrative examples corresponding to two different initial conditions are presented: a high-mass, high-concentration case that starts with a disk of 0.24 [FORMULA] extending up to 15 A.U. from the star, and a low-mass, low-concentration case that starts with a disk of 0.02 [FORMULA] extending up to 250 A.U. from the star. The high-mass model leads to all solids being lost to the star; however, the low-mass model leads to a radial distribution of solid material quite reminiscent of what is found in our solar system.

Key words: accretion disks – solar system: formation

© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998