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Planet formation - Mechanism of early growthExperiments in vacuum (approx. 0.5 to 1 mbar) and in air quantify mechanics of collisions, rebound, and fragmentation at low velocities (1-50 m/sec), under the conditions usually postulated for the preplanetary environment in the primitive solar nebula. Such collisions have been little studied experimentally. Contrary to widespread assumptions, accretionary growth of the largest meteoroid- and asteroid-sized bodies in a given swarm results spontaneously from the simple mechanics of these collisions, without other ad hoc sticking mechanisms. The smaller bodies in the swarm are less likely to grow. Granular surfaces form, either by gravitational collapse of dust swarms or by rapid formation of regolith surfaces on solid planetesimals; these surfaces strongly promote further growth by retarding rebound. Growth of large bodies increases modal collision velocities, causing fragmentation of smaller bodies and eventual production of interstellar dust as a by-product of planetesimal interactions.
Document ID
19780039246
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hartmann, W. K.
(Planetary Science Institute Tucson, Ariz., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1978
Publication Information
Publication: Icarus
Volume: 33
Subject Category
Lunar And Planetary Exploration
Accession Number
78A23155
Funding Number(s)
CONTRACT_GRANT: NSG-7201
CONTRACT_GRANT: NASW-2909
Distribution Limits
Public
Copyright
Other

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