Explosive Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars. II — Heavy-Element Nucleosynthesis of s, p, r-Processes —

We investigate the nucleosynthesis in a massive star of 70 Mwith solar metallicity in the main sequence stage. The helium core mass after hydrogen burning corresponds to 32 M� . Nucleosynthesis calculations have been performed during the stellar evolution and the jetlike supernova explosion of a collapsar model. We focus on the production of elements heavier than iron group nuclei. Nucleosynthesis calculations have been accomplished consistently from hydrostatic to dynamic stages by using large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. We confirm that s-elements of 60 90 are produced via photodisintegrations of seed s-elements. However, the produced p-elements are disintegrated in later stages except for 180 Ta. In the explosive nucleosynthesis, elements of 90 50) are overproduced via the p-process because of the low peak temperatures in the oxygen- and neon-rich layers. Compared with the previous study of r-process nucleosynthesis calculations in the collapsar model of 40 Mby Fujimoto et al. (S. Fujimoto, M. Hashimoto, K. Kotake and S. Yamada, Astrophys. J. 656 (2007), 382; S. Fujimoto, N. Nishimura and M. Hashimoto, Astrophys. J. 680 (2008), 1350), our jet model cannot contribute to the third peak of the solar r-elements and intermediate p-elements, which have been much produced because of the distribution of the lowest part of electron fraction in the ejecta. Averaging the overproduction factors over the progenitor masses with the use of Salpeter's IMF, we suggest that the 70 Mstar could contribute to the solar weak s-elements of 60