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Kozo Sadakane, Eiji Kambe, Bun’ei Sato, Satoshi Honda, Osamu Hashimoto, An Abundance Analysis of the Primary Star of the Peculiar Eclipsing Binary |$\epsilon$| Aurigae out of the Eclipsing Phase, Publications of the Astronomical Society of Japan, Volume 62, Issue 6, 25 December 2010, Pages 1381–1390, https://doi.org/10.1093/pasj/62.6.1381
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Abstract
A detailed abundance analysis of the primary star of |$\epsilon$| Aur before an eclipse was carried out using a very high signal-to-noise ratio optical-region spectrum. An A7 Iab supergiant HD 81471, presumably a member of the Vela OB1 association, was used as a reference. We obtained atmospheric parameters (T|$_{\rm eff}$|, log g, and |$\xi_{\rm t}$|) to be (8025 K, 1.0 and 10 km s|$^{-1}$|) and (8050 K, 1.0 and 7 km s|$^{-1}$|) for |$\epsilon$| Aur and HD 81471, respectively. The abundances of Mg, Si, S, Ca, Sc, Ti, Cr, and Fe were very close to the solar abundances in both stars. Light elements C and O were under-abundant, while N and Na were over-abundant in both stars, after correcting for non-LTE effects. Definite under-abundances of Sr were detected in both stars. Slight, but definite, over-abundances were found in |$\epsilon$| Aur for the s-process elements Y, Zr, and Ba, when compared with the results of HD 81471. Enhancements in the abundances of N, Na, and s-process elements might indicate the occurences of thermal dredge-up and the s-process nucleosynthesis in |$\epsilon$| Aur during the past evolution.
