Studies in Common Envelope Evolution

Northwestern University, Evanston IL

Investigators

Abstract

AST-0200876 PI Taam The observed masses and orbital periods for many classes of close binary star systems are difficult to reproduce in evolutionary scenarios without significant angular momentum and mass loss. A mechanism which facilitates these losses involves the transfer of orbital angular momentum and energy to a common envelope which is subsequently ejected as a result of the gravitational interactions between the two components. This common envelope phase of evolution will be investigated in this project for massive stars (as applied to low mass X-ray binaries containing neutron stars and black holes)as well as low to intermediate mass stars (as applied to cataclysmic variables containing white dwarf stars). The primary goal of the research will be to determine the parameters for which the progenitor binary systems at long orbital periods are transformed and survive as short period systems, and the parameters for which mergers takes place. These investigations include the treatment of multi-dimensional hydrodynamical processes, and in this proposal the investigators will undertake high resolution three dimensional studies of the common envelope phase using an adaptive, parallel simulation code. This research provides a foundation upon which the formation and evolution of close binary systems containing compact objects can be understood. ***