2005/12/21 by Anna Frebel, Norbert Christlieb, John E. Norris +2 · 7 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/500592
published as Astrophys.J.638:L17-L20,2006 · 13 pages, accepted for publication in ApJL
arxiv created 2005/12/21 · openalex publication_date 2006/01/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
From a newly obtained VLT/UVES spectrum, we have determined the oxygen abundance of HE 1327-2326, the most iron-poor star known to date. Ultraviolet OH lines yield one-dimensional LTE abundances of [O/Fe] OH = 3.7 (subgiant case) and [O/Fe] OH = 3.4 (dwarf case). Using a correction of -1.0 dex to account for three-dimensional (3D) effects on OH line formation, the abundances are lowered to [O/Fe] = 2.8 and [O/Fe] = 2.5, respectively, which we adopt. Without 3D corrections, the UV OH-based abundance would be in disagreement with the upper limits derived from the O I triplet lines: [O/Fe] trip < 2.8 (subgiant) and [O/Fe] trip < 3.0 (dwarf). We also correct the previously determined carbon and nitrogen abundances for 3D effects. Knowledge of the O abundance of HE 1327-2326 has implications for the interpretation of its abundance pattern. A large O abundance is in accordance with HE 1327-2326 being an early Population II star that formed from material chemically enriched by a first-generation supernova. Our derived abundances, however, do not exclude other possibilities such as a Population III scenario.