Sulphur abundance in very metal-poor stars
نویسنده
چکیده
We have obtained high-resolution high signal-to-noise spectra of the S i nearinfrared doublet at 8694 Å in eight metal-poor stars with metallicities in the range −0.6 ≤[Fe/H]≤ −3.0. Elemental sulphur abundances were derived for six targets and upper limits were set for two of the most metal-poor stars in the sample. The sulphur doublet at 8694.62 Å has been detected in three stars (HD19445, HD2665 and HD2796) with [Fe/H]≤ −1.9. Our observations combined with those available in the literature indicate a monotonic increase of the [S/Fe] ratio as [Fe/H] decreases, reaching values [S/Fe]∼0.7-0.8 below [Fe/H]=−2. We discuss plausible scenarios for interpretation of these results. Subject headings: Galaxy: evolution — nuclear reactions, nucleosynthesis, abundances — stars: abundances — stars: late-type — stars: Population II
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