23/05/2012 – 14h00 – Auditório IAG – IAG/USP

Alejandro Raga


Título/Title: "Weak shock" supernova remnants in high pressure environments


Part of the damage done by blast waves from "ground based" explosions occurs at relatively large distances from the center, where the shock wave has already left the "strong shock" regime. A similar situation is found in SN explosions within high pressure regions (e.g., inside pre-existing hot bubbles or within molecular clouds), in which the hot bubble produced by the explosion reaches pressure equilibrium with the surrounding ISM, and the outer shock evolves into a weak, sonic compression wave. We have developed a new version of the "thin shell" blast wave model of Chernyi (1957, which reproduces the Sedov regime of a blast wave), in which we allow the outer shock to have the general strong/weak shock jump relations (Chernyi assumed that the shock is strong). Somewhat surprisingly, this extended problem also leads to a full analytic solution, which apparently has been missed in all of the work done on the theory of blast waves. Comparing our new analytic solution with predictions from a spherically symmetric numerical simulation (with the full gasdynamic equations), we find that it reproduces the deviations from the Taylor-Sedov solution that occur at large evolutionary times (when the outer shock is no longer strong). Finally, this talk will describe the implications of the new solutions for the case of supernova explosions occurring within pre-existing hot bubbles or within molecular clouds.

Download the video:
05-23-2012_Weak_shock_supernova_.avi (49min, 96MB)

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