An analytic model for the strong-/weak-shock transition in a spherical blast wave

The solution of a non-radiative, strong, spherical blast wave has been derived from an approximate model of a low-density hot bubble which drives a thin shell (which contains most of the displaced environmental material). We show that this model can be extended to the case in which the blast wave is no longer strong, leading to a full analytic solution. We then compare this analytic model with a numerical solution of the full spherically symmetric Euler equations. Finally, we discuss possible applications of the analytic model to supernovae that explode within pre-existing hot bubbles, or inside dense molecular clouds.