Multidimensional Simulations of Convection Preceding a Type I

Type I X-ray bursts are thermonuclear explosions on the surfaces of neutron stars that can be used to determine the mass and radius of the underlying neutron star and hence help constrain the equation of state for dense matter. Particularly important is our physical understanding of how a localized, subsonic burning front ignites and spreads, the state of the material in which the burning front propagates, and the extent to which heat released from reactions expands the photosphere of the neutron star. Multidimen-sional simulation of low Mach number astrophysical flows, such as the propagation of a flame or the slow convective turnover, in such systems have been rather restricted in the past; fully compressible hydrodynamics algorithms have a time step size that is constrained by the propagation of acoustic waves, which can be neglected in low iii Mach number flows of this type. This thesis presents results of multidimensional, plane-parallel simulations of the con-vection preceding ignition in a Type I X-ray burst. I use a low Mach number hydro-dynamics code, MAESTRO, based on a low Mach number approximation that filter