Dwarf novae (DN) are a class of nova and cataclysmic variable that have multiple observed eruptions ranging in brightness from 2 to 5 magnitudes. Outburst intervals for each object are quasi-periodic, but within the DN family, intervals can range from days to decades. The lifetime of an outburst is typically from 2 to 20 days and is related to the outburst interval. DN outbursts are usually attributed to the release of gravitational energy resulting from an instability in the accretion disk or by sudden mass-transfers through the disk.

In the case of recurrent novae and classical novae, a shell of ejected matter can be detected spectroscopically, while dwarf novae exhibit no such behavior.

Within the DN family, there are three subtypes.

1. Z Cam stars exhibit standstills about 0.7 magnitudes below the maximum brightness. Outbursts cease during these standstills for tens of days to years.

2. SU UMa stars exhibit occasional superoutbursts which are typically 0.7 magnitudes brighter than normal outbursts. The outburst lifetime in these cases is on the order of 5 times the lifetime of a normal outburst.

3. U Gem stars include all DN that are not members of the above subtypes.

Cataclysmic Variable, Classical Nova, Nova, Recurrent Nova