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Letter to the Editor
Abundance analysis of two extremely metal-poor stars from the Hamburg/ESO Survey *
E. Depagne 1,
V. Hill 2,
N. Christlieb 3 and
F. Primas 2
Received 10 August 2000 / Accepted 25 August 2000
We report on the first high spectral resolution analysis of extremely metal-poor halo stars from the Hamburg/ESO objective-prism survey (HES). The spectra 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 metal abundances of and -3.20, respectively. The stellar parameters derived from the UVES spectra are in very good agreement with those derived from moderate-resolution follow-up spectra. HE 1353-2735 is a double-lined spectroscopic binary.
The two stars nicely reproduce the strong scatter in [Sr/Fe] observed for extremely metal-poor stars. While we see a strong Sr II Å line in the spectrum of HE 1303-2708 (), we can only give an upper limit for HE 1353-2735 (), since the line is not detected. 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 these stars, to a level which places them among Lithium-plateau metal-poor dwarfs.
Key words: stars: abundances stars: binaries: spectroscopic stars: fundamental parameters stars: individual: stars: subdwarfs surveys
Send offprint requests to: Eric.Depagne@obspm.fr
Online publication: December 15, 2000