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A Model of Silicate Grain Nucleation and Growth in Circumstellar OutflowsBased on its abundance, high bond energy, and recent measurements of its vapor pressure SiO is a natural candidate for dust nucleation in circumstellar outflows around asymptotic giant branch stars. In this paper, we describe a model of the nucleation and growth of silicate dust in such outflows. The sensitivity of the model to varying choices of poorly constrained chemical parameters is explored, and the merits of using scaled rather than classical nucleation theory are briefly considered, An elaboration of the model that includes magnesium and iron as growth species is then presented and discussed. The composition of the bulk of the grains derived from the model is consistent with olivines and pyroxenes, but somewhat metal-rich grains and very small, nearly pure SiO grains are also produced,
Document ID
20110013566
Document Type
Reprint (Version printed in journal)
Authors
Paquette, John A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ferguson, Frank T. (Catholic Univ. of America Washington, DC, United States)
Nuth, Joseph A., III (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 25, 2013
Publication Date
April 5, 2011
Publication Information
Publication: The Astrophysical Journal
Volume: 732
Issue: 2
Subject Category
Astrophysics
Report/Patent Number
GSFC.JA.4656.2011
Distribution Limits
Public
Copyright
Other