THE PRIMORDIAL ABUNDANCE OF LI-6 AND BE-9

Light element (Li-6, Li-7, and Be-9) depletion isochrones for halo stars have been calculated with standard stellar evolution models. These models include the latest available opacities and are computed through the subgiant branch. If Li-6 is not produced in appreciable amounts by stellar flares, then the detection of Li-6 in HD 84937 by Smith, Lambert, & Nissen is compatible with standard stellar evolution and standard big bang nucleosynthesis only if HD 84937 is a subgiant. The present parallax is inconsistent with HD 84937 being a subgiant star at the 2.5 sigma level. The most metal poor star with a measured Be-9 abundance is HD 140283, which is a relatively cool subgiant. Standard stellar evolution predicts that Be-9 will have been depleted in this star by approximately 0.3 dex (for T(eff) = 5640 K). Revising the abundance upward changes the oxygen-beryllium relation, suggesting incompatibility with standard cosmic-ray production models, and hence, standard big bang nucleosynthesis. However, an increase in the derived temperature of HD 140283 to 5740 K would result in little depletion of Be-9 and agreement with standard big bang nucleosynthesis.