Density (left panel) and temperature (right panel) slices of the binary system during the merger at the time when it reaches conditions for carbon ignition. The purple circle shows the point where 32 cells reach a temperature of 10⁹ K at a density of 2 × 10⁶ g cm⁻³. We ignited a detonation there (see text). The contours in the left panel show the origin of 95% of the material that will become the bound remnant after the explosion. The crosses in the left panel show the centres of mass of the material originating from each white dwarf.