Abundances of Big Bang elements

Abstract

In this paper we review the present status of observations of the Big Bang elements D, 3He, 4He and 7Li and of their extrapolation to the primordial values. It is shown that, within the errors, the abundances are consistent with the predictions of the standard Big Bang nucleosynthesis for 1 < eta_10 < 6, which corresponds to 0.004 < Omega_b h_{0}^2 < 0.02$. Narrower consistencies in eta_{10} are still possible at about 1.7 or about 4, but in this case some of the observations of D and 4He should be incorrect. Finally, it is noted that &#34;extragalactic&#34; Li may have already been detected in a star possibly accreted by the Galaxy.