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Aggregation of grains in a turbulent pre-solar diskThe growth and evolution of grains in the protostellar nebula are investigated within the context of turbulent low-mass disk models developed by previous investigators. Because of grain collisions promoted by the turbulent velocities, particles aggregate to millimeter size in times of the order of 1000 yrs. During the growth the particles acquire a large inward radial velocity due to gas drag (Weidenschilling, 1977) and spiral into the sun. The calculations indicate that the final size of the particles does not exceed a few centimeters. This result is not very sensitive to the specific nebula parameters. For all conditions investigated it seems impossible to grow meter- or kilometer-sized bodies that could decouple from the gas motion. An additional argument is given that shows that only particles smaller than centimeter size can survive drift into the growing sun by being transported radially outward by turbulent mixing. This agrees well with the maximum size of inclusions and chondrules. Since sedimentation of grains and subsequent dust disk instability is effectively inhibited by turbulent stirring, the formation of planetesimals and planets cannot be explained in the above scenario without further assumptions.
Document ID
19850044396
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Wieneke, B.
(Rice Univ. Houston, TX, United States)
Clayton, D. D.
(Rice University Houston, TX, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1983
Subject Category
Lunar And Planetary Exploration
Accession Number
85A26547
Funding Number(s)
CONTRACT_GRANT: NSG-7361
Distribution Limits
Public
Copyright
Other

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