2002/07/08 by P. E. Nissen, Nissen, P. E., Y. Q. Chen +6
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0207163
10 pages, 4 figures, 2 tables. To appear in proceedings of IAU Symp. 210, "Modelling of Stellar Atmospheres", ASP Conference Series, 2002, Eds. N. Piskunov, W.W. Weiss and D.F. Gray
arxiv created 2002/07/08 · openalex publication_date 2002/07/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
From equivalent widths of the SI lines at 8694 A, Israelian & Rebolo (2001) and Takada-Hidai et al. (2002) have derived a surprisingly high sulphur-to-iron ratio ([S/Fe] = 0.5 to 0.7) in six halo stars with [Fe/H] ~ -2.0 suggesting perhaps that hypernovae made a significant contribution to the formation of elements in the early Galaxy. To investigate this problem we have used high-resolution spectra obtained with the ESO VLT/UVES spectrograph to determine the S/Fe ratio in 19 main-sequence and subgiant stars ranging in [Fe/H] from -3.2 to -0.7. The sulphur abundances are determined from SI lines at 8694 A and 9212 - 9237 A, and the iron abundances from about 20 FeII lines. S/Fe ratios as derived from 1D model atmospheres are presented and possible 3D effects are discussed. The initial results from our survey do not confirm the high values of [S/Fe] quoted above; instead we find that the ratio [S/Fe] remains constant at about 0.35 dex for metallicities -3 < [Fe/H] -1.