The sudden increase in energy expels the atmosphere into interstellar space creating the envelope seen as visible light during the nova event and in past centuries mistaken as a "new" star. A few novae produce short-lived nova remnants, lasting for perhaps several centuries. Recurrent nova processes are the same as the classical nova, except that the fusion ignition may be repetitive because the companion star can again feed the dense atmosphere of the white dwarf.

Although the term "stella nova" means "new star", novae most often take place as a result of white dwarfs, which are remnants of extremely old stars.

Novae are classified according to the light curve development speed, so in