The evolution of young supernova remnants

The results obtained from numerical modelling of young supernova remnants (SNR), particularly with regard to the effects on expansion of a constant stellar wind from the progenitor star, are reported. A one-dimensional Lagrangian program described the hydrodynamic evolution of the SNR, including the velocity, radius and temperature of the expanding shell for a given initial explosive energy. The presence of the wind is noted to reduce the effect of the shock temperature. An accompanying steep outer density profile could cause a deceleration of the expansion produced by reverse shocks encountering mass elements of the ejecta. A Sedov phase may in fact be prevented by the wind.