KECK-NIRSPEC INFRARED OH LINES: OXYGEN ABUNDANCES IN METAL-POOR STARS DOWN TO [Fe/H]
نویسنده
چکیده
Infrared OH lines at 1.5 1.7 μm in the H band were obtained with the NIRSPEC highresolution spectrograph at the 10m Keck Telescope for a sample of seven metal-poor stars. Detailed analyses have been carried out, based on optical high-resolution data obtained with the FEROS spectrograph at ESO. Stellar parameters were derived by adopting infrared flux method effective temperatures, trigonometric and/or evolutionary gravities and metallicities from Fe II lines. We obtain that the sample stars with metallicities [Fe/H] < −2.2 show a mean oxygen abundance [O/Fe] ≈ 0.54, for a solar oxygen abundance of ǫ(O) = ≈ 8.87, or [O/Fe] ≈ 0.64 if ǫ(O) = 8.77 is assumed.
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