Doctor of Philosophy (PhD)


Physics and Astronomy

Document Type



We present a numerical method for the study of double white dwarf (DWD) binary systems at the onset of super-Eddington mass transfer. We incorporate the physics of ideal inviscid hydrodynamical flow, Newtonian self-gravity, and radiation transport on a three-dimensional uniformly rotating cylindrical Eulerian grid. Our new method conserves total energy to a higher degree of accuracy than recent smoothed particle hydrodynamics methods and our previous Eulerian grid based method. We present the results of verification tests and we simulate the first 20+ orbits of a binary system of mass ratio q=0.7 at the onset of dynamically unstable direct impact mass transfer. Although the mass transfer rate exceeds the critical Eddington limit by many orders of magnitude, it appears to have very little effect on the accretion flow. We also model over 20 orbits of a DWD of mass ratio q=0.4. In these simulations, the accretion stream detaches from the accretor after 4 orbits and an asymmetric accretion torus forms. We submit these DWD models as the first self-consistent three dimensional simulations of mass transferring DWDs incorporating radiation transport.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Tohline, Joel E.