Influence of Inelastic Collisions with Hydrogen Atoms on Non-LTE Oxygen Abundance Determination in the Sun and late-type stars

Abstract: We present the non-local thermodynamic equilibrium (non-LTE) calculations for O I with the updated model atom that includes quantum-mechanical rate coefficients for O I + H I inelastic collisions from the recent study of Barklem (2018). The non-LTE abundances from the O I lines were determined for the Sun and 46 FG stars in a wide metallicity range, -2.6 < [Fe/H] < 0.2. An application of accurate atomic data leads to larger departures from LTE and lower oxygen abundances compared to that for the Drawin's theoretical approximation. For the infrared O I 7771-5 A triplet lines, the change in the non-LTE abundance is -0.11 dex for the solar atmospheric parameters and decreases in absolute value towards lower metallicity. We revised the [O/Fe]-[Fe/H] trend derived in our earlier study. The change in [O/Fe] is small in the [Fe/H] range from -1.5 to 0.2. For stars with [Fe/H] < -1, the [O/Fe] ratio has increased such that [O/Fe] = 0.60 at [Fe/H] = -0.8 and increases up to [O/Fe] = 0.75 at [Fe/H] = -2.6.