Sulphur abundances in metal-poor stars

Abstract

We report on sulphur abundances in halo stars as derived from near-IR UVES spectra. The importance of removing telluric lines and residual CCD fringing patterns by using early B-type stars as calibrators is emphasized. Comparison of data from the weak λ8694.6 and the stronger λ9212.9,9237.5 pair of S I lines provides important constraints on non-LTE effects. We do not confirm the high sulphur abundances reported by others for some metal-poor stars; our results instead indicate that sulphur behaves like other typical α-capture elements with a plateau at [S/Fe] ∼ + 0.3 dex in the Galactic halo. © 2008 Springer-Verlag Berlin Heidelberg.