Are some CEMP-s stars the daughters of spinstars?

Abstract

CEMP-s stars are long-lived low-mass stars with a very low iron content as well as overabundances of carbon and s-elements. Their peculiar chemical pattern is often explained by pollution from a AGB star companion. Recent observations have shown that most of the CEMP-s stars are in a binary system, providing support to the AGB companion scenario. A few CEMP-s stars, however, appear to be single. We inspect four apparently single CEMP-s stars and discuss the possibility that they formed from the ejecta of a previous-generation massive star, referred to as the "source" star. In order to investigate this scenario, we computed low-metallicity massive star models with and without rotation and including complete s-process nucleosynthesis. We find that non-rotating source stars cannot explain the observed abundance of any of the four CEMP-s stars. Three out of the four CEMP-s stars can be explained by a $25$ $M_{\odot }$ source star with $v_{\mathrm{ini}}\sim 500$ km s${}^{-1}$ (spinstar). The fourth CEMP-s star has a high Pb abundance that cannot be explained by any of the models we computed. Since spinstars and AGB predict different ranges of [O/Fe] and [ls/hs], these ratios could be an interesting way to further test these two scenarios.

4 pages, accepted for publication in A&A

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Cited by in corpus (9)

• Evidence for an aspherical Population III supernova explosion inferred from the hyper metal-poor star HE1327-2326
• Learning about the intermediate neutron-capture process from lead abundances
• Abundances and kinematics of carbon-enhanced metal-poor stars in the Galactic halo*; A new classification scheme based on Sr and Ba
• Origin of the CEMP-no Group Morphology in the Milky Way
• The R-Process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
• Neutron-capture elements in dwarf galaxies II: Challenges for the s- and i-processes at low metallicity
• Inferring the velocity of early massive stars from the abundances of extremely metal-poor stars
• A strong neutron burst in jet-like supernovae of spinstars
• A direct measurement of the 17O(a,g)21Ne reaction in inverse kinematics and its impact on heavy element production