Analysis Of The Elemental Abundances About 14 Galactic S-process Enriched Post AGB Stars

Post AGB star has finished all AGB evolution stages,and its elemental abundance distribution clearly shows the final evolution result of AGB stars.Analysis its elemental abundance plays an important role for studying the formation and evolution of AGB star.It's important to do quantitative analysis to elemental abundance with data and diagrams for studying post AGB star,where elements include ?-elements(O,Mg,Si,Ca,Ti),some iron group elements(Sc,V,Cr,Fe,Co,Ni)and neutron-capture elements(Y,Zr,Ba,La,Ce,Pr,Nd,Sm,Eu).In order to study the reasons why the elemental abundance of 14 galaxy s-process enriched post AGB stars was abnormal,we use five components elemental abundance model to calculate and fit the elemental abundance of stars.The result shows that when [Fe/H] varies from-0.18 to-0.91,the component coefficient of main s-process Cs,mof 14 sample stars is much higher than that of the solar system,and the component coefficient of weak r-process Cr,w,the component coefficient of weak s-process Cs,w and the component coefficient of SNe la CI,a are all similar to those of the solar system.And specially,the component coefficient of the main r-process Cr,m of the sample stars is also relatively biger,which indicates that both main s-process and main r-process contribute a lot to elemental abundance.Moreover,We compared the abundances of sample stars with the elemental abundances of 20 stars that had been identified to have enriched by the main r-process and the main s-process.We found that their elemental abundance was similar,and we suggested that the sample stars have the same astrophysical origins with the 20 stars.?-elements Mg ?Si ?Ga are taken as examples.Here the secondary component contribution and SNe la component contribution increase,while primary component contribution decreases.They are mainly from the primary process,where its secondary component contribution counts,but SNe la component contribution could be ignored.For some iron group elements,Fe is mainly from the primary process,secondary component contribution and SNe la component contribution increase,and especially,SNe la component contribution tends to be the main component contribution.The secondary component contribution of Mn and Ni are higher than primary component contribution and SNe la component contribution,the variation trends of each component contribution are gentle.Neutron-capture elements Y ?Zr are taken as examples.Each component contribution tends to be relatively steady,where s-process component contribution plays a leading role,the main r-process component contribution is also big,weak r-process component contribution tends to decrease a little,and weak s-process component contribution can be ignored.For examples of La ?Nd?Sm,the main s-process component contribution plays a leading role,the main r-process component contribution is also big,and weak r-process component contribution can be ignored.For examples of Eu?Gd,their main r-process component contributing both play a leading role.Main s-process component contribution of Eu can't be ignored,and even its contribution to Gd is almost same as contribution of main r-process to Gd.