2005/09/09 by Yoichi Takeda, Osamu Hashimoto, Hikaru Taguchi +4 · 132 citations
Physics and Astronomy · #Abundance (ecology) #Astronomy and Astrophysical Research #Consistency (knowledge bases) #Electrical and Electromagnetic Research #Plateau (mathematics) #Spectral line #Stars #Stellar, planetary, and galactic studies #Sulfur #Zinc #astro-ph
paper · pdf · doi:10.1093/pasj/57.5.751
published in Publications of the Astronomical Society of Japan 57(5), 751-768 (Oxford University Press) · 33 pages, 7 figures, PASJ, Vol. 57, No. 5 (2005) in press
arxiv created 2005/09/09 · openalex publication_date 2005/10/25 · arxiv updated 2015/06/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract Extensive statistical-equilibrium calculations on S I and Zn I were carried out, in order to investigate how the non-LTE effect plays a role in the determination of their abundances in F–K stars. Having checked on the spectra of representative F-type stars (Polaris, Procyon, α Per) and the Sun that our non-LTE corrections yield a reasonable consistency between the abundances derived from different lines, we tried an extensive non-LTE reanalysis of published equivalent-width data of S I and Zn I lines for metal-poor halo/disk stars. According to our calculations, S I 9212/9228/9237 lines suffer significant negative non-LTE corrections (\lesssim 0.2 \hbox-- 0.3 dex), while LTE is practically valid for S I 8683/8694 lines. As far as the very metal-poor regime is concerned, a marked discordance is observed between the [S/Fe] values from these two abundance indicators, in the sense that the former attains a nearly flat plateau (or even a slight downward bending) while the latter shows an ever-increasing trend with a further lowering of metallicity. The characteristics of [Zn/Fe] reported from recent LTE studies (i.e., an evident/slight increase of [Zn/Fe] with a decrease of [Fe/H] for very metal-poor/disk stars) were almost confirmed, since the non-LTE corrections for the Zn I 4722/4810 and 6362 lines (tending to be positive and gradually increasing toward lower [Fe/H]) are quantitatively of less significance (\lesssim 0.1 dex).