Title page for ETD etd-11042011-122517


Type of Document Dissertation
Author Marcello, Dominic Carlo
Author's Email Address dmarce1@lsu.edu, dmarcello4@gmail.com
URN etd-11042011-122517
Title Numerical Methods for the Study of Super-Eddington Mass Transfer in Double White Dwarf Binaries
Degree Doctor of Philosophy (Ph.D.)
Department Physics & Astronomy
Advisory Committee
Advisor Name Title
Tohline, Joel E. Committee Chair
Frank, Juhan Committee Member
Hynes, Robert I. Committee Member
Lee, Hwang Committee Member
Moldovan, Dorel Dean's Representative
Keywords
  • merger
  • radiation hydrodynamics
  • mass loss
  • flux-limited diffusion
  • advection
  • central scheme
  • close binaries
  • common envelope
Date of Defense 2011-07-22
Availability unrestricted
Abstract
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.
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