Carbon, nitrogen and oxygen abundances in Betelgeuse. (original) (raw)
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Abstract
Elemental abundances of C, N, and O in the red M supergiant Belegeuse are discussed to characterize their source. The discussion is based on previous data on weak CO second-overtone V-R lines near 1.6 micron, the NH fundamental V-R 1-0 and 2-1 bands between 3 and 4 microns, the OH fundamental V-R bands near 3 microns, and the CN red system lines near 2 microns. Attention is also given to the forbidden O I lines and the 8000 A CN red system lines, and to comparisons between models for the stellar atmosphere and the data. A model for an effective temperature of 3800 K, a surface gravity of 0.0, and a microturbulence of 4 km/sec is adopted which, if Betelgeuse is metal rich, would require forbidden lines of Fe/H to be near 0.1. The forbidden CNO would be -0.04 relative to the sun. The C/N ratio is nonsolar, which suggests contamination of the Betelgeuse atmosphere with CN processed material.
Publication:
The Astrophysical Journal
Pub Date:
September 1984
DOI:
Bibcode:
Keywords:
- Carbon Stars;
- Nuclear Fusion;
- Red Giant Stars;
- Stellar Composition;
- Stellar Cores;
- Supergiant Stars;
- Abundance;
- Infrared Spectra;
- M Stars;
- Nitrogen;
- Oxygen;
- Stellar Atmospheres;
- Stellar Models;
- Stellar Spectra;
- Vibrational Spectra;
- Astrophysics