The Abundance of Boron in Three Halo Stars
Abstract
B abundances for three halo stars: HD 140283, HD 19445, and HD 201891 are presented. Using recent determinations of the Be abundance in HD 140283, B/Be of 10 +5/-4 is found for this star, and similar ratios are inferred for HD 19445 and HD 201891. This ratio is equal to the minimum value of 10 expected from a synthesis of B and Be by high-energy cosmic-ray spallation reactions in the interstellar medium. It is shown that the accompanying synthesis of Li by alpha on alpha fusion reactions is probably a minor contributor to the observed 'primordial' Li of halo stars. The observed constant ratios of B/O and Be/O are expected if the principal channel of synthesis involves cosmic-ray CNO nuclei from the supernovae colliding with interstellar protons.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1992
- DOI:
- 10.1086/172088
- Bibcode:
- 1992ApJ...401..584D
- Keywords:
-
- Boron;
- Dwarf Stars;
- Galactic Halos;
- Stellar Spectra;
- Abundance;
- Cosmic Rays;
- Milky Way Galaxy;
- Spectrographs;
- Stellar Atmospheres;
- Ultraviolet Spectra;
- Astrophysics;
- GALAXY: HALO;
- NUCLEAR REACTIONS;
- NUCLEOSYNTHESIS;
- ABUNDANCES;
- STARS: ABUNDANCES;
- ULTRAVIOLET: STARS