The heavy-element abundances of AGB stars and the angular momentum   conservation model of wind accretion for barium stars
  Adpoting new s-process nucleosynthesis scenario and branch s-process path, we calculate the heavy-element abundances and C/O ratio of solar metallicity 3M_sun TP-AGB stars. The evolutionary sequence from M to S to C stars of AGB stars is explained naturally by the calculated results. Then combining the angular momentum conservation model of wind accretion with the heavy-element abundances on the surface of TP-AGB stars, we calculate the heavy-element overabundances of barium stars via successive pulsed accreting and mixing. Our results support that the barium stars with longer orbital period, P>1600 days, form through wind accretion scenario. 
Y. C. Liang (1,3), G. Zhao (1,3), B. Zhang (2,4) ((1) Beijing Astro.   Obs., (2) Hebei Normal Univ. (3) National Astro. Obs....