We revisit the Galactic chemical evolution of oxygen , addressing the systematic errors inherent in classical determinations of the oxygen abundance that arise from the use of one dimensional hydrostatic ( 1D ) model atmospheres and from the assumption of local thermodynamic equilibrium ( LTE ) .
We perform detailed 3D non-LTE radiative transfer calculations for atomic oxygen lines across a grid of 3D hydrodynamic stagger model atmospheres for dwarfs and subgiants .
We apply our grid of predicted line strengths of the [ Oi ] 630 nm and Oi 777 nm lines using accurate stellar parameters from the literature .
We infer a steep decay in [ O/Fe ] for \text { [ Fe / H ] } \gtrsim - 1.0 , a plateau \text { [ O / Fe ] } \approx 0.5 down to \text { [ Fe / H ] } \approx - 2.5 and an increasing trend for \text { [ Fe / H ] } \lesssim - 2.5 .
Our 3D non-LTE calculations yield overall concordant results from the two oxygen abundance diagnostics .