Massive Binaries: Dynamical and Evolutionary Transformations

Observations of massive binaries offer us key insight about the formation, evolution, and destinies of massive stars. Here I review some advances in observational and theoretical studies of massive binaries. Surveys for binaries using radial velocity, photometric, and high angular resolution methods show that the binary frequency is high for 0 stars in clusters. Evolutionary models for interacting binaries demonstrate the importance of angular momentum transfer during Roche lobe overflow. The mass gainer may reach critical rotation and stem further accretion, and there are many observed cases that show the consequences of such mass loss and transfer. New hydrodynamical models describe colliding wind physics in eccentric binaries such as eta Carinae and WR 140. All these research topics are championed by Tony Moffat, and the current richness of this field is due in large measure to his energetic pursuits.