Abundance analysis of two extremely metal-poor stars from the Hamburg/ESO Survey

We report on the first high spectral resolution analysis of extremely metal -poor halo stars from the Hamburg/ESO objective-prism survey (HES). The spe ctra were obtained with UVES at VLT-UT2. The two stars under investigation (HE 1303-2708 and HE 1353-2735) are main-sequence turnoff-stars having meta l abundances of [Fe/H] = -2.85 and -3.20, respectively The stellar paramete rs derived from the UVES spectra are in very good agreement with those deri ved from moderate-resolution follow-up spectra. HE 1353-2735 is a double-Li ned spectroscopic binary. The two stars nicely reproduce the strong scatter in [Sr/Fe] observed for e xtremely metal-poor stars. While we see a strong Sr II lambda 4215 Angstrom line in the spectrum of HE 1303-2708 ([Sr/Fe] = -0.08), we can only five a n upper limit for HE 1353-2735 ([Sr/Fe] < -1.2), since the line is not dete cted. We report abundances of Mg, Ca, Sc, Ti, Cr for both stars, and Co, Y for HE 1303-2708 only. These abundances do not show any abnormalities with respect to known trends for metal-poor stars. Lithium is also detected in t hese stars, to a level which places them among Lithium-plateau metal-poor d warfs.