Nucleosynthesis in massive stars

In this paper we discuss recent theoretical results about nucleosynthesis in massive stars. First, we outline that rotation is able to alter the evolution and the chemical yields of massive stars substantially. Current models predict furthermore that the collapsing core which initiates typical Type II supernova explosions reaches critical rotation during the collapse. We then discuss the effects of a close binary partner on the nucleosynthesis yields of massive stars. Most important, we find that the output of radioactive Al-26 from secondary components of massive close binaries is so tremendous that it may dominate the Galactic Al-26 production.