Recent Chandra and XMM Newton observations of the point X-ray source population in the Milky Way and external galaxies have led to a resurgence of interest in the evolution of close interacting binary systems with compact components. The observed masses and orbital periods for these systems are difficult to understand and require significant loss of both mass and angular momentum. An evolutionary channel which facilitates these losses involves the transfer of angular momentum and energy from the binary orbit to a common envelope which is subsequently ejected.
This so-called common envelope phase of binary evolution will be investigated in this project. Particular attention will be focused on the formation of cataclysmic variable binary systems containing white dwarf compact stars as well as on intermediate and low mass X-ray binaries containing neutron star and black hole components. The primary goal of this research is to delineate the regions in parameter space separating progenitor systems in which the binary is transformed from one at long orbital periods to one at short orbital periods as a post common envelope survivor from systems which merge into a single rapidly rotating object.
These studies will involve the treatment of multi-dimensional hydrodynamical processes and require high resolution three dimensional numerical simulations. To carry out these simulations, an adaptive, parallel simulation code that has been especially modified to treat the common envelope problem will be employed. The research will ultimately provide a foundation upon which the formation and evolution of close binary systems containing compact objects can be understood.
The impact of these projects is expected to be felt across a broad spectrum of contemporary astrophysics including X-ray astronomy, gravitational theory, supernova theory, and cataclysmic variable star research. In addition, it will aid in the training and education of human resources in science since the numerical techniques and methodologies involved in the efficient use of high performance parallel computing architectures and the data management skills required for the solution of these problems have many applications outside of the specific areas focused upon here. The results will be visualized for the general public at the Adler Planetarium & Astronomy Museum in Chicago. The goal will be to show to the public the importance of visualization in scientific discovery for research as well to convey that such tools can be effective means for learning scientific ideas. The results will also be incorporated into both introductory and advanced courses offered by the Department of Physics and Astronomy at Northwestern University.
