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Coagulation of grains in static and collapsing protostellar cloudsThe wavelength dependence of extinction in the diffuse interstellar medium implies that it is produced by particles of dominant size of approximately 10(exp -5) cm. There is some indication that in the cores of dense molecular clouds, sub-micron grains can coagulate to form larger particles; this process is probably driven by turbulence. The most primitive meteorites (carbonaceous chondrites) are composed of particles with a bimodal size distribution with peaks near 1 micron (matrix) and 1 mm (chondrules). Models for chondrule formation that involve processing of presolar material by chemical reactions or through an accretion shock during infall assume that aggregates of the requisite mass could form before or during collapse. The effectiveness of coagulation during collapse has been disputed; it appears to depend on specific assumptions. The first results of detailed numerical modeling of spatial and temporal variations of particle sizes in presolar clouds, both static and collapsing, is reported in this article.
Document ID
Document Type
Conference Paper
Weidenschilling, S. J. (Arizona Univ. Tucson, AZ, United States)
Ruzmaikina, T. V. (Academy of Sciences USSR, Moscow., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Lunar and Planetary Inst., Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z
Subject Category
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19940015909Analytic PrimaryWorkshop on the Martian Northern Plains: Sedimentological, Periglacial, and Paleoclimatic Evolution19940016163Analytic PrimaryTwenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z