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s- and r-process elements in two very metal-poor stars

Sean G. Ryan·Wako Aoki·Lisa A. J. Blake·John E. Norris·Timothy C. Beers·Roberto Gallino·Maurizio Busso·Hiroyasu Ando
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Abstract

New measurements of neutron-capture elements are presented for two very metal-poor stars ([Fe/H] ~ -3). One (LP 625-44) has an s-process signature believed to be due to mass transfer from a now-extinct metal-poor AGB companion, and the second (CS 22897-008) is one of a number of very metal-poor stars having high [Sr/Ba] ratios which is not expected from the r-process. In the s-process star, many elements including lead have been detected, providing strong constraints on the 13C pocket in the now-extinct AGB star. In the Sr-rich star, Zn, Y, and Zr are also seen to be overabundant, and several possible nucleosynthesis mechanisms are discussed.

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Sean G. Ryan, Wako Aoki, Lisa A. J. Blake, John E. Norris, Timothy C. Beers, Roberto Gallino, Maurizio Busso, Hiroyasu Ando. 2000-08-28. s- and r-process elements in two very metal-poor stars. https://arxiv.org/abs/astro-ph/0008423

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