The overabundance of s-process elements in Ba stars through wind accretion

The lack of self consistency in the current wind accretion models is pointed out. Taking account of δr ≠ 0, the modification equations of orbital parameters are re-deduced. Combined with wind accretion scenarios, calculations of nucleosynthesis for intrinsic AGB stars are first used to calculate s-process enrichments of Ba stars. Comparisons are also made between the predictions of calculations and the observations. It is found that predictions from the model for the standard case are an upper limit to the observations. Better agreements are obtained either by increasing the wind velocity or reducing the accretion rate.