thumb |upright=1.2 |[[GK Persei: Nova of 1901 – remnant]]
A nova remnant is made up of the material either left behind by a sudden explosive fusion eruption by classical novae, or from multiple ejections by recurrent novae. Over their short lifetimes, nova shells show expansion velocities of around 1000 km/s, whose faint nebulosities are usually illuminated by their progenitor stars via light echoes as observed with the spherical shell or the energies remaining in the expanding bubbles like T Pyxidis.
Form
thumb |Nova [[T Pyxidis – remnant]]
Most novae require a close binary system, with a white dwarf and a main sequence, sub-giant, or red giant star, or the merging of two red dwarfs, so probably all nova remnants must be associated with binaries. This theoretically means these nebula shapes might be affected by their central progenitor stars and the amount of matter ejected by novae.