Oxygen abundance in halo stars from OI triplet

Oxygen abundance for 14 halo stars through the O I 7774 Angstrom triplet ha ve been derived from high resolution spectra (R = 25.000; S/N > 100) obtain ed with echelle-spectrometer of 6-m telescope of Special Astrophysical Obse rvatory of the Russian Academy of Sciences. The effective temperature, meta llicity and other parameters have been examined. For example, the effective temperature was found from H-alpha line wings and photometric indices. The abundance analysis was carried out using both LTE and non-LTE conceptions. For this aim, we have specified the oxygen atomic model. The average [O/Fe] value appeared to be 0.61 +/- 0.21 from the non-LTE dete rmination. A trend of oxygen abundance increasing along with the iron abund ance decreasing was found. The relation between [O/Fe] and [Fe/H] is linear : [O/Fe] = -0.370 x [Fe/H] + 0.047. In addition to the sample of our progra m stars, we also involved in the analysis, 24 targets from Cavallo et al. ( 1997). For their original results we have determined the necessary non-LTE corrections. Our data are compared with the results of other works (Tomkin et al., 1992; King & Boesgaard, 1995; Boesgaard et al. 1999).