A D6 thermonuclear supernova, 50 s after the explosion, from Tanikawa et al 2018. D6 stands for dynamically-driven (violent mass transfer) double-degenerate (two white dwarfs orbiting each other) double-detonation (first in the outer He layer, then in the C+O core, of the primary WD).
Shown are iso-contours of the mass density, 4 contours in the inner ejecta, at levels 8%, 4%, 2%, 1% of the max from red to yellow, and 2 contours in the outer layers, at levels 1e-4 and 1e-5 of the max in white.
The elongated tail is where the first detonation folded over on itself on the surface of the primary white dwarf. The conical feature is the shadow from the companion white dwarf, that was cast on the exploding primary white dwarf after the second detonation.