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Paper: Observational Constraints on Circumstellar Carbon Grains
Volume: 309, Astrophysics of Dust
Page: 321
Authors: Jura, M.
Abstract: Available observations can be used to constrain the sizes and composition of dust grains around mass-losing carbon stars. For example, around the best studied star of this class, IRC+10216, consideration of both the maps of molecules such as CN together with the map of the 2.2 μm reflection nebulosity allows us to infer a particle size distribution where the particle radius is typically near 0.1 μm. In contrast, in the markedly bipolar outflow around RAFGL 2688, the Egg Nebula, there are some grains as large as 0.3 cm in radius. Most of the grains in the out- flows from carbon stars appear to be largely composed of carbon. Recent laboratory work suggests that graphitic onions may be an appropriate model for the structure of many of these carbon particles.
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