to a homologous expansion and a moment of complete hydrogen recombination. In the optimal model D11, the characteristic moments are $t_1 \approx 0.93$ days, $t_2 \approx 18$ days, $t_3 \approx 94$ days, $t_4 \approx 116$ days, $t_5 \approx 124$ days, and $t_6 \approx 150$ days, and the complete hydrogen recombination occurs at $t_\mathrm{H} \approx 111.3$ days. Below we consider the basic stages in the time development of the optimal model.

Shock breakout {#sec:dmd-shbrk}
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The explosion of the star is assumed to be triggered by a piston action near the edge of the central core immediately after the epoch zero, $t=0$. From here on, $t$ is the time in the comoving frame of reference. This energy release generates a strong shock wave that propagates towards the stellar surface. In moving out of the center, the shock wave heats matter and accelerates it to velocities increasing outward and exceeding the local escape velocity. From $t=0.0065$ days to $t=0.2416$ days, the shock wave, propagating outward from the compact dense core of the pre-SN (Fig. \[fig:rhomr\]), is attenuated slightly due to the spherical divergence (Fig. \[fig:velvsm\]). It then reaches the outermost layers with a sharp decline in density and after $t=0.6234$ days gains 