2003/07/03 by J. P. Fulbright, Jon P. Fulbright, Jennifer A. Johnson · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/377443
published as Astrophys.J.595:1154-1181,2003 · 41 pages, 12 tables, 17 figures. Accepted for publication in Oct. 2003 ApJ
arxiv created 2003/07/03 · openalex publication_date 2003/09/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present oxygen abundances derived from both the permitted and forbidden oxygen lines for 55 subgiants and giants with [Fe/H] values between -2.7 and solar with the goal of understanding the discrepancy in the derived abundances. A first attempt, using T eff values from photometric calibrations and surface gravities from luminosities obtained agreement between the indicators for turn-off stars, but the disagreement was large for evolved stars. We find that the difference in the oxygen abundances derived from the permitted and forbidden lines is most strongly affected by T eff , and we derive a new T eff scale based on forcing the two sets of lines to give the same oxygen abundances. These new parameters, however, do not agree with other observables, such as theoretical isochrones or Balmer-line profile based T eff determinations. Our analysis finds that one-dimensional, LTE analyses (with published non-LTE corrections for the permitted lines) cannot fully resolve the disagreement in the two indicators without adopting a temperature scale that is incompatible with other temperature indicators. We also find no evidence of circumstellar emission in the forbidden lines, removing such emission as a possible cause for the discrepancy.