Multidimensional Simulations of Convection Preceding a Type I X-ray Burst on the Surface of a Neutron Star
SUNY, Stony Brook
The surface explosion that occurs in a Type I X-ray burst (XRB) is strongly influenced by the underlying neutron star parameters, such as mass, radius, and rotational frequency, making XRBs interesting tools to help constrain the equation of satate of dense matter. A complete theoretical understanding of the burst phenomenon, including the ignition and propogation of the subsonic burn front, will instruct us how to use these tools. In the past it has been computationally difficult to model XRBs in multiple dimensions because of the low Mach number flow and the large range of physical scales of the system. I present results of the early convective phase preceding ignition of an XRB using the low Mach number approximation code MAESTRO, which filters acoustic wavs from the system while retaining important compressible effects due to background stratification, reactions, thermal diffucion, and compositional changes. I characterize the convective pattrns that form and discuss their resulting influence on the state of the convective region, which is important in modeling the outburst itself.