Abstract

Determination of the cosmic abundance of the light elements Li, Be and B is critical for the understanding of how these elements have been formed in the Universe. The Standard Model for the Big Bang nucleosynthesis, which assumes a uniform density, and its complementary model, the Non-uniform Density Model (see e.g. Kajino and Boyd, 1990), differ considerably in their predictions of Be- and B-production . However, recent determinations of the abundance of Be (Gilmore et al. 1991) and B (Duncan et al. 1992) in metal-poor stars are orders of magnitude larger than those predicted from any Big Bang nucleosynthesis model. The isotopes ⁹Be, ¹⁰B and ¹¹B are therefore thought to have been produced by cosmic spallation, primarily when high-energy protons and α-particles collide with CNO nuclei in the interstellar medium.

© 1992 Optical Society of America