Explosive Combustion of a Neutron Star into a Quark Star: the non-premixed scenario

We review aspects of the hydrodynamical combustion of nuclear matter to strange quark matter in a neutron star. Numerical studies on non-premixed combustion that consistently include hydrodynamical flows in a reactive-diffusive setup show that in 1D, the conversion (burning) front moves at sub-sonic speeds. Although the front eventually comes to a halt (in the star's reference frame), it still has ud matter falling onto it, and so is capable of converting the rest of the star. However, in the process, we also find that neutrino cooling of the interface causes it to wrinkle, laying a platform for a deflagrative-to-detonative transition (DDT). We outline progress on improvements in the burning code (Burn-UD: http://quarknova.ucalgary.ca/software/Burn-UD/) that will ultimately reveal the mechanism that can explode the outermost layers of even a dense compact object like a neutron star.