SIMBAD references

LTE and non-LTE (NLTE) abundances of sulfur in six metal-poor giants and 61 dwarfs (62 dwarfs including the Sun) were explored in the range of -3≲[Fe/H]≲+0.5 using high-resolution, high signal-to-noise ratio spectra of the S I 8693.9 and 8694.6 Å lines observed by us and measured by Franois and Clegg, Lambert, & Tomkin. NLTE effects in S abundances are found to be small and practically negligible. The behavior of [S/Fe] versus [Fe/H] exhibits a linear increasing trend without plateau with decreasing [Fe/H]. Combining our results with those available in the literature, we find that the slope of the increasing trend is -0.25 in the NLTE behavior of [S/Fe], which is comparable to that observed in [O/Fe]. The observed behavior of S may require chemical evolution models of the Galaxy, in which scenarios of hypernovae nucleosynthesis and/or time-delayed deposition into interstellar medium are incorporated.