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A. K. Speck (Unversity of Missouri - Columbia)
It has been known for more than three decades that dust particles form in the atmospheres of cool stars and are ejected into the interstellar medium (e.g. Gilman 1969, Friedemann 1969, Gilra 1971, Woolf 1973). In this context there has been a great deal of work published on silicon carbide (SiC). From equilibrium condensation models, Friedemann (1969) and Gilman (1969) showed that SiC should condense in the atmospheres of carbon-rich AGB stars. Following the work of Gilra & Code (1971), Hackwell (1972) and Treffers & Cohen (1974), a broad infrared emission feature seen in the spectra of many carbon stars, peaking between about 11.0 and 11.5\mum, has been attributed to solid SiC particles although the exact nature of these particles is still disputed. Silicon carbide grains are also found in meteorites. From isotopic studies, many of these grains are believed to have formed around carbon-rich AGB stars, with a small number also coming from Novae and Supernovae. Furthermore, SiC is not detected in the interstellar medium (Whittet, Duley & Martin 1990). Since the discovery of SiC 11\mum feature in carbon star spectra, and fueled by the discovery of presolar SiC grains in meteorites, there has been a great deal of observational, experimental and theoretical study of silicon carbide as stardust. We present a review of silicon carbide in the cosmos and how this enigmatic little mineral has helped our understanding of stardust and stellar evolution in general, as well as changing our views of experimental astrophysics and astromineralogy.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.