The Rosseland mean opacity of interstellar grains

• Published in: Astrophysics and space science Vol. 188; no. 1; pp. 109 - 116
• Main Authors: ALI, A, EL-NAWAWY, M. S, EL SHALABY, M. A
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer 01-02-1992
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Interstellar medium (ism) and nebulae in milky way; Stellar systems. Galactic and extragalactic objects and systems. The universe; Theoretical model; Graphite; Numerical simulation; Opacity; Silicates; Interstellar grain; Interstellar matter
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/BF00642927

The opacity of interstellar grains in the temperature range 10-1500 K is calculated. Two composite grain models have been considered. One of them consists of silicate coated with an ice mantle and the second has a graphite core coated also with an ice mantle. These models are compared with isolated grain models. An exact analytical and computational development of Guttler's formulas for composite grain models has been used to calculate the extinction coefficient. It has been found that the thickness of the mantle affects the opacity of the interstellar grains. The opacity of composite models differs from that of the isolated models. The effect of the different species (ice, silicate, and graphite) is also clear. (Author)