Title: Computing the dust distribution in the bow shock of a fast moving, evolved star
Authors: van Marle, Allard Jan ×
Meliani, Zakaria
Keppens, Rony
Decin, Leen #
Issue Date: Jun-2011
Publisher: University of Chicago Press for the American Astronomical Society
Series Title: Astrophysical Journal vol:734 issue:2 pages:L26-L30
Abstract: We study the hydrodynamical behavior occurring in the turbulent interaction zone of a fast-moving red supergiant star, where the circumstellar and interstellar material collide. In this wind-interstellar-medium collision, the familiar bow shock, contact discontinuity, and wind termination shock morphology form, with localized instability development. Our model includes a detailed treatment of dust grains in the stellar wind and takes into account the drag forces between dust and gas. The dust is treated as pressureless gas components binned per grain size, for which we use 10 representative grain size bins. Our simulations allow us to deduce how dust grains of varying sizes become distributed throughout the circumstellar medium. We show that smaller dust grains (radius <0.045 μm) tend to be strongly bound to the gas and therefore follow the gas density distribution closely, with intricate fine structure due to essentially hydrodynamical instabilities at the wind-related contact discontinuity. Larger grains which are more resistant to drag forces are shown to have their own unique dust distribution, with progressive deviations from the gas morphology. Specifically, small dust grains stay entirely within the zone bound by shocked wind material. The large grains are capable of leaving the shocked wind layer and can penetrate into the shocked or even unshocked interstellar medium. Depending on how the number of dust grains varies with grain size, this should leave a clear imprint in infrared observations of bow shocks of red supergiants and other evolved star
ISSN: 0004-637X
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Plasma-astrophysics Section
Institute of Astronomy
× corresponding author
# (joint) last author

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