Big bang nucleosynthesis (BBN) and the cosmic baryon density from cosmic microwave background anisotropies together predict a primordial 7Li abundance a factor of 2-3 higher than that observed in galactic halo dwarf stars. A recent analysis of 7Li observations in halo stars, using significantly higher surface temperature for these stars, found a higher Li plateau abundance. These results go a long way toward resolving the discrepancy with BBN. Here we examine the implications of the higher surface temperatures on the abundances of Be and B that are thought to have been produced in galactic cosmic-ray nucleosynthesis by spallation of CNO together with Li (produced in α + α collisions). While the Be abundance is not overly sensitive to the surface temperature, the derived B abundances and more importantly the derived oxygen abundances are very temperature-dependent. If the new temperature scale is correct, the implied increased abundances of these elements pose a serious challenge to models of galactic cosmic-ray nucleosynthesis and galactic chemical evolution.
- Cosmic rays
- Early universe
- Nuclear reactions, nucleosynthesis, abundances
- Stars: abundances