2000/11/02 by M. Asplund, Asplund, M.
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0011043
Invited talk presented at IAU General Assembly Joint Discussion 8 "Oxygen abundances in old stars and implications for nucleosynthesis and cosmology", Manchester, August 2000. The full version of the talk can be found at http://www.astro.uu.se/~martin/talks/Manchester00
The formation of [O I], O I and OH lines in metal-poor stars has been studied by means of 3D hydrodynamical model atmospheres. For O I detailed 3D non-LTE calculations have been performed. While the influence of 3D model atmospheres is minor for [O I] and O I lines, the very low temperatures encountered at low metallicities have a drastic impact on the OH lines. As a result, the derived O abundances are found to be systematically overestimated in 1D analyses, casting doubts on the recent claims for a monotonic increase in [O/Fe] towards lower metallicities.