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arXiv · 1405.4185

Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars

W. Y. Cui·B. Zhang·J. R. Shi·G. Zhao·W. J. Wang·P. Niu
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Abstract

We study the abundance distributions of a sample of metal-rich barium stars provided by Pereira et al. (2011) to investigate the s- and r-process nucleosynthesis in the metal-rich environment. We compared the theoretical results predicted by a parametric model with the observed abundances of the metal-rich barium stars. We found that six barium stars have a significant r-process characteristic, and we divided the barium stars into two groups: the r-rich barium stars ($C_r>5.0$, [La/Nd]\,$<0$) and normal barium stars. The behavior of the r-rich barium stars seems more like that of the metal-poor r-rich and CEMP-r/s stars. We suggest that the most possible formation mechanism for these stars is the s-process pollution, although their abundance patterns can be fitted very well when the pre-enrichment hypothesis is included. The fact that we can not explain them well using the s-process nucleosynthesis alone may be due to our incomplete knowledge on the production of Nd, Eu, and other relevant elements by the s-process in metal-rich and super metal-rich environments (see details in Pereira et al. 2011).

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W. Y. Cui, B. Zhang, J. R. Shi, G. Zhao, W. J. Wang, P. Niu. 2014-05-16. Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars. https://doi.org/10.1051/0004-6361/201323295

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