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 (26)

• The Spitzer Space Telescope Mission
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• The Infrared Spectrograph on the Spitzer Space Telescope
• New Interstellar Dust Models Consistent with Extinction, Emission, and Abundance Constraints
• Scattering by Interstellar Dust Grains: Optical and Ultraviolet
• User Guide for the Discrete Dipole Approximation Code DDSCAT (Version 5a10)
• C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth
• The shape and composition of interstellar silicate grains
• Dust in the diffuse interstellar medium: Extinction, emission, linear and circular polarisation
• Chandra Observation of the Edge-on Spiral NGC 5775: Probing the Hot Galactic Disk/Halo Connection
• CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations
• Modelling the optical properties of composite and porous interstellar grains
• Dust extinction and absorption: the challenge of porous grains
• The composition and size distribution of the dust in the coma of comet Hale-Bopp
• The infrared emission spectra of compositionally inhomogeneous aggregates composed of irregularly shaped constituents
• Is the silicate emission feature only influenced by grain size?
• Effect of dust grain porosity on the appearance of protoplanetary disks
• The Spitzer Spectroscopic Survey of S-type Stars
• Effects of Grain Size on the Spectral Energy Distribution of Dusty Circumstellar Envelopes
• Interstellar Extinction by Spheroidal Dust Grains
• Composite Interstellar Grains
• Automated Classification of 2000 Bright IRAS Sources
• Systematic variations of interstellar linear polarization and growth of dust grains
• IRAS 17423-1755 (Hen 3-1475) revisited: an O-rich high-mass post-Asymptotic Giant Branch star
• Infrared Emission from the Composite Grains: Effects of Inclusions and Porosities on the 10 and 18 $\mu m$ Features
• Composite Grains: Effects of Porosity and Inclusions on the 10$\mu$m Silicate Feature

Cited by in corpus (1)

• Modelling the mid-infrared polarization in dust around young stars