Carbon and nitrogen abundances in F and G type stars.
Abstract
Carbon and nitrogen abundances have been obtained for a sample of 11-F- and G-type dwarfs covering a range in Fe/H abundance ratio from -0.8 to +0.3. Model atmospheres, which included the effects of convection and line blanketing, were used to calculate synthetic spectra of the CH, CN, and NH molecular bands. Effective oscillator strengths for the bands studied were found by matching synthetic spectra calculated from a model solar atmosphere with the observed solar bands. Many of the metal-poor stars, and particularly the high-velocity stars, were found to have substantial nitrogen over-deficiencies, suggesting that N is manufactured mostly in a secondary manner. The carbon-to-iron ratios were similar to the solar ratio, although there may be slight C over-deficiencies in metal-poor stars. However, the variation in C/Fe is not as marked as that found recently by Hearnshaw (1974). A comprehensive discussion of the theoretical errors is given, and some applications to Galactic evolution are noted.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 1977
- DOI:
- 10.1093/mnras/181.1.1
- Bibcode:
- 1977MNRAS.181....1C
- Keywords:
-
- Abundance;
- Carbon;
- Dwarf Stars;
- F Stars;
- G Stars;
- Nitrogen;
- Stellar Atmospheres;
- Atmospheric Composition;
- Atmospheric Models;
- Error Analysis;
- Galactic Evolution;
- Late Stars;
- Solar Spectra;
- Stellar Models;
- Astrophysics;
- CATALOGS (PUBLICATIONS);
- COS-B SATELLITE;
- GALACTIC RADIATION;
- GAMMA RAYS;
- SATELLITE OBSERVATION;
- COSMIC RAYS;
- EMISSION;
- RADIATION SOURCES;
- SPATIAL DISTRIBUTION;
- Space Radiation