The beryllium abundance in the very metal-poor halo star G 64-12 from VLT/UVES observations

We report on a new spectroscopic analysis of the very metal deficient star G 64-12 ([Fe/H] = -3.3), aimed at determining, for the first time, its bery llium content. The spectra were observed during the Science Verification of UVES, the ESO VLT Ultraviolet and Visible Echelle Spectrograph. The high r esolution (similar to 48 000) and high S/N (similar to 130 per pixel) achie ved at the wavelengths of the Be II resonance doublet allowed an accurate d etermination of its abundance: log N(Be/H) = -13.10 +/- 0.15 dex. The Be ab undance is significantly higher than expected from previous measurements of Be in stars of similar metallicity (3D and NLTE corrections acting to make a slightly higher value than an LTE analysis). When compared to iron, the high [Be/Fe] ratio thus found may suggest a flattening in the beryllium evo lutionary trend at the lowest metallicity end or the presence of dispersion at early epochs of galactic evolution.