Evolution of Tycho's supernova remnant

The evolution of Tycho's supernova remnant has been modeled with a numerical calculation based on a similarity solution developed by Chevalier in 1982. The new model has one important addition: a shell of matter, presumably a presupernova planetary nebula, is needed around the exploding white dwarf in order to reproduce some features in the observed morphology of the SNR. In particular, a very thin ''rim'' surrounding the main shell of the SNR cannot be reproduced without the planetary nebula. The evolution has been followed from a time of 107 s to the present epoch (1.3 x 1010 s). The results include predictions of the radial distribution of relative brightness in both X-ray and radio wavelengths