Comparing the Nucleosynthesis Parameters of s+r Stars and Ba Stars

Wen-Yuan Cui, Dong-Nuan Cui, Bo Zhang
2008 Proceedings of the International Astronomical Union  
AbstractIn this paper, we use a parametric model of the asymptotic giant branch (AGB) stars, in which the13C neutron source is activated in radiative conditions during the interpulse periods, to calculate the nucleosynthesis in 29 very metal-poor double-enhanced stars (i.e. s+r stars) and 26 barium stars (i.e. Ba stars), respectively. Through a statistical analyzing on the corresponding parameters obtained for the above stars, we get the possible conditions which the s+r stars formed in. We
more » ... s formed in. We find that the value of neutron exposures of most s+r stars is greater than that of Ba stars. In the very metal-poor stars, the Ba stars stars should belong to the binary systems with large initial orbital separation, by comparing the s-process-component coefficient (Cs) values with those of s+r stars. For s+r stars, there is strong correlation between theirCsandCr(r-process-component coefficient) but no correlation for Ba stars. This strongly confirms the possibility that the s+r stars should form through the accretion-induced collapse (AIC) or type 1.5 supernova mechanism.
doi:10.1017/s1743921308022576 fatcat:lvqc3gphijfxfluoyz3ri2k2lu