Flame surface (gray) and density isosurfaces of ρ = 10²,  10³,  10⁴,  10⁵,  10⁶,  10⁷ g cm⁻³ (see colorbar) for model r60_d2.6. Left panel: situation prior to detonation initiation at t = 4.7 s. Middle panel: zoom in on the core at t = 4.78 s. The hotspot with temperatures above 1 × 10⁹ K is marked by the blue-green contour. Right panel: detonation front (blue surface) ∼1 s after initiation. The illustration is not to scale.