SIMBAD references

2003ApJ...595.1154F - Astrophys. J., 595, 1154-1181 (2003/October-1)

Oxygen abundances in metal-poor stars.


Abstract (from CDS):

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 Teffvalues 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 Teff, and we derive a new Teffscale 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 Teffdeterminations. 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.

Abstract Copyright:

Journal keyword(s): Stars: Abundances - Stars: Atmospheres - Stars: Fundamental Parameters

VizieR on-line data: <Available at CDS (J/ApJ/595/1154): tables 3 .. 12>

Simbad objects: 56

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