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标题：The impact of the 18F(a,p)21Ne reaction on fluorine production in asymptotic giant branch stars
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作者：A.I. Karakas
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2008
卷号：2008
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The recent experimental evaluation of the 18F(a,p)21Ne reaction rate, when considering its associated uncertainties, presented significant differences compared to the theoretical Hauser-Feshbach rate. This was most apparent at the low temperatures relevant for He-shell burning in asymptotic giant branch (AGB) stars. Investigations into the effect on AGB nucleosynthesis revealed that the upper limit resulted in an enhanced production of 19F and 21Ne in carbon-rich AGB models, but the recommended and lower limits presented no differences from using the theoretical rate. This was the case for models spanning a range in metallicity from solar to [Fe/H] ∼ −2.3. The results of this study are relevant for observations of F and C-enriched AGB stars in the Galaxy, and to the Ne composition of mainstream silicon carbide grains, that supposedly formed in the outflows of cool, carbon-rich giant stars. We discuss the mechanism that produces the extra F and summarize our main findings.