Large molecules in the envelope surrounding IRC+10216 |
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Authors: | T. J. Millar E. Herbst R. P. A. Bettens |
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Affiliation: | Department of Physics, UMIST, PO Box 88, Manchester M60 1QD;Departments of Physics and Astronomy, The Ohio State University, Columbus, OH 43210, USA;Research School of Chemistry, Australian National University, ACT 0200, Australia |
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Abstract: | A new chemical model of the circumstellar envelope surrounding the carbon-rich star IRC+10216 is developed that includes carbon-containing molecules with up to 23 carbon atoms. The model consists of 3851 reactions involving 407 gas-phase species. Sizeable abundances of a variety of large molecules including carbon clusters, unsaturated hydrocarbons and cyanopolyynes have been calculated. Negative molecular ions of chemical formulae and C n H (7 n 23) exist in considerable abundance, with peak concentrations at distances from the central star somewhat greater than their neutral counterparts. The negative ions might be detected in radio emission, or even in the optical absorption of background field stars. The calculated radial distributions of the carbon-chain C n H radicals are looked at carefully and compared with interferometric observations. |
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Keywords: | molecular data molecular processes circumstellar matter stars: individual: IRC+10216 ISM: molecules |
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