Massive Star Mergers: Induced Mixing and Nucleosynthesis

We study the nucleosynthesis and the induced mixing during the merging of massive stars inside a common envelope. The systems of interest are close binaries, initially consisting of a massive red supergiant and a main-sequence companion of a few solar masses. We apply parameterized results based on hydrodynamical simulations to model the stream-core interaction and the response of the star in a standard stellar-evolution code. Preliminary results are presented illustrating the possibility of unusual nucleosynthesis and post-merging dredge-up which can cause composition anomalies in the supergiant's envelope. This revised version was published online in September 2006 with corrections to the Cover Date.