Composite Circumstellar Dust Grains

Abstract

We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\mu \mathrm{m}$. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18$\mu \mathrm{m}$. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-Type \& AGB stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes; shape; composition and dust temperature.

10 pages, 11 Figures

References in corpus (7)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• The shape and composition of interstellar silicate grains
• CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations
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• Composite Interstellar Grains
• Composite Grains: Effects of Porosity and Inclusions on the 10$\mu$m Silicate Feature