An upper limit to the abundance of 9Be in the population II star HD 76932 from a high resolution spectrum with the IUE.

Abstract

A high resolution spectrum (Δλ = 0.2 Å) of the Population II star HD 76932 from the archive of the IUE satellite has been analysed in a search for measurable resonance absorption lines due to ⁹Be. Matching the observations by a synthesized model of the wavelength region around the doublet at 3130 Å gives a conservative upper limit for the abundance ⁹Be/H in the star of 3×10^-12. When all alternatives for the production modes of ⁹Be and ⁷Li have been considered, this result strongly supports a primordial origin for ⁷Li. The primordial ⁷Li is the best method now available for estimation of the universal baryon/photon ratio η; the range of η derived appears to set a severe constraint on the number of two-component neutrino types permitted within the context of standard Big Bang model.