Behavior of [S/Fe] in Very Metal-Poor Stars from the S I 1.046 μm Lines Revisited

With an aim to establish how the [S=Fe] ratios behave in the very low metallicity regime down to [Fe=H] �� 3, we conducted a non-LTE analysis of near-IR S I triplet lines (multiplet 3) at 10455–10459 u A for a dozen very metalpoor stars (� 3.2 . [Fe=H] . � 1.9) based on new observational data obtained with IRCS+AO188 of the Subaru Telescope. It turned out that the resulting [S=Fe] values are only moderately supersolar at [S=Fe] � +0.2–0.5, irrespective of the metallicity. While this “flat” tendency is consistent with a trend recently corroborated by Spite et al. (2011, AA the likely cause for this failure is also discussed.