Beryllium in main-sequence stars.
Abstract
Beryllium abundances are determined in 38 main-sequence F and G stars, including the sun. Values of log g are estimated from the positions of the stars on the Stromgren diagram, effective temperatures are obtained from previous H-beta photometry, and the Be abundances are determined via an LTE abundance analysis using the standard model atmospheres of Carbon and Gingerich (1969). The results show that the mean Be abundance (relative to H) in F and G dwarfs is 1.3 by 10 to the -11th power, that there is no discernible dependence of Be abundance on temperature, and that the mean abundance reported represents the cosmic abundance. It is demonstrated that the origin of Be can be explained in terms of galactic cosmic-ray spallation reactions in the interstellar gas. One-third of the stars hotter than 6600 K (spectral type F6) are shown to be both Be- and Li-deficient; it is suggested that microscopic and turbulent diffusion appear to offer the most promising way to account for the observed depletions.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1976
- DOI:
- Bibcode:
- 1976ApJ...210..466B
- Keywords:
-
- Abundance;
- Beryllium;
- Main Sequence Stars;
- Stellar Atmospheres;
- Atmospheric Models;
- Cosmic Rays;
- Dwarf Stars;
- F Stars;
- G Stars;
- Interstellar Gas;
- Nuclear Fusion;
- Spallation;
- Stellar Luminosity;
- Stellar Temperature;
- Thermodynamic Equilibrium;
- Ultraviolet Spectra;
- Astrophysics