Published online by Cambridge University Press: 12 April 2016
Several years after outburst, extended optical emission can be seen around many classical novae. Common features include shells, polar ‘blobs’, equatorial rings and, at least in the case of DQ Her (1934), tropical rings above and below the ‘equator’. We present hydrodynamic calculations of the dynamical effects of the underlying binary system on the material ejected during outburst, and show that many of the features observed in the optical remnants of novae can be reproduced. Polar blobs, banded shells and spherical shells can all be obtained in the model, depending on the speed class of the nova.