Oxygen abundances: new results from [O I] lines

Abstract

Abstract Supersolar oxygen-to-iron ratios are known to exist in nearly all metal-poor stars. But there is no general agreement on the magnitude of these relative overabundances. New high resolution spectra of evolved stars over a large metallicity range have been gathered, from which lines of [O I], Sc II, and Fe II have been measured. Abundance ratios [O/Sc] and [O/Fe], insensitive to most model atmospheric uncertainties, have been derived and correlated with overall metallicity. These ratios both are consistent with earlier studies of the [O I] lines in metal-poor stars: [O/Sc]≃[O/Fe]≃+0.4, with possibly a small upward trend with decreasing [Fe/H].