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

Molaro, P.; Beckman, J.
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Astronomy and Astrophysics (ISSN 0004-6361), vol. 139, no. 2, Oct. 1984, p. 394-400. Research supported by the Osservatorio Astronomico di Trieste.

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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.