2002/08/01 by W. Aoki, Wako Aoki, S. G. Ryan +8 · 7 citations
Physics and Astronomy · #Astro and Planetary Science #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/343885
published as Astrophys.J.580:1149-1158,2002 · 23 pages, 3 figures, ApJ, in press
arxiv created 2002/08/01 · openalex publication_date 2002/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
We report the abundances of neutron-capture elements in eight carbon-rich, metal-poor (-2.7 ≤ [Fe/H] ≤ -1.9) stars observed with the Subaru Telescope High Dispersion Spectrograph. The derived abundance patterns indicate that the neutron-capture elements in these objects primarily originated from s -process nucleosynthesis, although the [Ba/Eu] abundance ratios in some objects are lower than that of the solar system s -process component. The present analysis has yielded the Pb abundances for seven objects as well as an upper limit for one object from use of the Pb I λ4057 and λ3683 lines. The values of [Pb/Ba] in these objects cover a wide range, between -0.3 and 1.2. Theoretical studies of s -process nucleosynthesis at low metallicity are required to explain this large dispersion of the [Pb/Ba] values. Variations in radial velocity have been found for two of the eight objects, suggesting that, at least in these instances, the observed excess of s -process elements is due to the transfer of material across a binary system including an AGB star. Comparisons with predictions of AGB nucleosynthesis models are discussed.