R-Process Nucleosynthesis and Galactic Chemical Evolution ofthe Ba Peak Elements

Nucleosynthesis yield is a very important parameter of the Galactic chemical evolution model. We adopt the same method of Tsujimoto to derive the r-process yields of various mass SNe II at low metallicities from the new observed Ba/Fe-Fe/H trend. %but we get rid of the stars such as CS22892-052, CS31082. Furthermore, we present a new formula of r-process nucleosynthesis yields. We also consider the various neutron sources and set up four cases, namely A, B, C and D to calculate the abundance evolution of Ba peak elements in the solar neighborhood. Our results show that the r-process could be associated with a secondary event in massive stars (i.e., 18M < M < 50). Therefore, the r-process could be associated with a secondary event in massive stars. Both the neutron source and the seed nuclei must be freshly manufactured by the stars instead of depending upon the initialmetallicity abundance.