We construct a model of interstellar dust in which H-rich amorphous carbon is deposited on silicate substrates in the interstellar medium, and is annealed to form H-poor amorphous carbon. The model grains are stratified spheres composed of hollow silicate cores coated with two carbonaceous layers, the inner layer of sp2 carbon and the outer layer of sp3 carbon. Using an accurate method of computing the optical properties of such layered grains, we explore the consequences of varying the core-grain size distribution and the thicknesses of the carbonaceous layers on the resulting infrared extinction. We find a wide dispersion in the curve morphology that reflects the grain size distributions and the chemical composition of dust materials.
Stratified dust grains in the interstellar medium. IIIInfrared cross-sections
CACCIOLA, ADRIANO;SAIJA, Rosalba;DENTI, Paolo;BORGHESE, Ferdinando
2011-01-01
Abstract
We construct a model of interstellar dust in which H-rich amorphous carbon is deposited on silicate substrates in the interstellar medium, and is annealed to form H-poor amorphous carbon. The model grains are stratified spheres composed of hollow silicate cores coated with two carbonaceous layers, the inner layer of sp2 carbon and the outer layer of sp3 carbon. Using an accurate method of computing the optical properties of such layered grains, we explore the consequences of varying the core-grain size distribution and the thicknesses of the carbonaceous layers on the resulting infrared extinction. We find a wide dispersion in the curve morphology that reflects the grain size distributions and the chemical composition of dust materials.Pubblicazioni consigliate
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