2003/04/02 by Christopher Sneden, C. Sneden, G. W. Preston +3
Physics and Astronomy · #Astronomy and Astrophysical Research #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/375705
published as Astrophys.J. 592 (2003) 504-515 · 34 pages, 9 figures, 7 tables; To appear in the Astrophysical Journal
arxiv created 2003/04/02 · openalex publication_date 2003/07/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present new abundance analyses of six blue metal-poor (BMP) stars with very low iron abundances ([Fe/H] < -2), based on new high-resolution echelle spectra. Three are spectroscopic binaries, and three have constant radial velocities. The chemical compositions of these two groups are very different, as the binary BMP stars have large enhancements of carbon and neutron-capture elements that are products of s -process nucleosynthesis. One star, CS 29497-030, has an extreme enhancement of lead, [Pb/Fe] = +3.7, the largest abundance in any star yet discovered. It probably also has an oxygen overabundance compared to the other BMP stars of our sample. The binary BMP stars must have attained their status via mass transfer during the asymptotic giant branch (AGB) evolutions of their companion stars, which are now unseen and most likely are compact objects. We have not found any examples of AGB mass transfer among BMP binaries with [Fe/H] > -2.