First UVES observations of beryllium in very metal-poor stars

We report on a attempt to detect beryllium in two dwarf stars of the Galact ic halo with metallicities below one thousandth solar. The data were obtain ed during the Commissioning of the Ultraviolet and Visible Echelle Spectrog raph (UVES) mounted on the ESO VLT Kuepen telescope, and show the potential of UVES for studies in the W-optical domain. We claim a beryllium detectio n in LP 815-43 ([Fe/H] similar to -2.95, [Be/H] = -13.09) at the 99.7% conf idence level, while only an upper limit can be set for the second target CD -24 degrees 17504 ([Fe/H] similar to -3.30, [Be/H] less than or equal to -1 3.39). These results suggest that the trend of beryllium with metallicity k eeps decreasing as lower metallicities are probed, with no evidence for fla ttening. hi CD-24 degrees 17504 we also analyzed the Li I line at 6708 Angs trom, and derived a lithium abundance close to the Spite plateau.