A nova is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star.
Artist's conception of a white dwarf star accreting hydrogen from a larger companion.
Nova: Before and after.
Nova cygni 1992.
Images of the star V838 Monocerotis.
Nova in M31 (Andromeda Galaxy)
V1500 Cyg (Nova Cygni 1975) Light Curve
Nova Eridani 2009 with a 14" telescope at 2009-11-30
Diagram of a Cataclysmic Variable