The asymmetry of a young supernova remnants propagating into an asymmetric circumstellar environment is studied with the aid of multi-dimensional hydrodynamic simulations. We assume the young supernova remnant is described by the self-similar driven wave solutions of Chevalier (1982- ApJ, 258, 790), propagating into an axisymmetric pre-supernova stellar wind, where the density of the wind is larger at the equator than the pole. For a large range of asymmetry functions and ratios of equatorial to polar densities, the aspect ratio (radius of SNR at the pole to that at the equator) of the remnant is close to that expected if there is only radial flow within the blastwave. However, if the density gradient at the pole is sufficiently large a strong vortex ring is generated, resulting in an anomously large aspect ratio. For example, using the asymmetry function of Luo & McCray (1991- ApJ, 379, 659) with a density ratio of only 4, the aspect ratio of the SSDW is greater than 3. The stability of such an asymmetric blastwave is confirmed with three-dimensional simulations.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1995