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Stochastic histories of dust grains in the interstellar mediumThe purpose is to study an evolving system of refractory dust grains within the Interstellar Medium (ISM). This is done via a combination of Monte Carlo processes and a system of partial differential equations, where refractory dust grains formed within supernova remnants and ejecta from high mass loss stars are subjected to the processes of sputtering and collisional fragmentation in the diffuse media and accretion within the cold molecular clouds. In order to record chemical detail, the authors take each new particle to consist of a superrefractory core plus a more massive refractory mantle. The particles are allowed to transfer to and fro between the different phases of the interstellar medium (ISM) - on a time scale of 10(exp 8) years - until either the particles are destroyed or the program finishes at a Galaxy time of 6x10(exp 9) years. The resulting chemical and size spectrum(s) are then applied to various astrophysical problems with the following results. For an ISM which has no collisional fragmentation of the dust grains, roughly 10 percent by mass of the most refractory material survives the rigors of the ISM intact, which leaves open the possibility that fossilized isotopically anomalous material may have been present within the primordial solar nebula. Stuctured or layered refractory dust grains within the model cannot explain the observed interstellar depletions of refractory material. Fragmentation due to grain-grain collisions in the diffuse phase plus the accretion of material in the molecular cloud phase can under certain circumstances cause a bimodal distribution in grain size.
Document ID
19910005685
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Liffman, Kurt (NASA Ames Research Center Moffett Field, CA., United States)
Clayton, D. D. (Rice Univ. Houston, TX., United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1989
Publication Information
Publication: Interstellar Dust: Contributed Papers
Subject Category
Astrophysics
Accession Number
91N14998
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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