Una estrella variable cataclísmica es un tipo de estrella variable que experimenta súbitos y espectaculares cambios en su brillo; también existen varibles con cambios minúsculos pero rápidos ("centelleo" o flickering), como GP Com, originados por la caída de material en la "mancha caliente" (Hot Spot) o zona de impacto del disco de acreción. Se pueden diferenciar los siguientes tipos: \n* Binarias cataclísmicas, que consisten en un sistema binario compuesto por una enana blanca y una enana roja o naranja de la secuencia principal que se hallan muy próximas. A su vez se subdividen en dos grupos: \n* Grupo no magnético, que incluye las novas enanas como la estrella U Geminorum. \n* Grupo magnético, que incluye las polares -objetos muy polarizados- como AM Herculis, y las polares intermedias como DQ Herculis. \n* Algunas clases de estrellas simbióticas, como Z Andromedae. \n* Toda clase de supernovas.

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Cataclysmic variable stars (CV) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state. They were initially called novae, from the Latin 'new', since ones with an outburst brightness visible to the naked eye and an invisible quiescent brightness appeared as new stars in the sky. Cataclysmic variable stars are binary stars that consist of two components; a white dwarf primary, and a mass transferring secondary. The stars are so close to each other that the gravity of the white dwarf distorts the secondary, and the white dwarf accretes matter from the companion. Therefore, the secondary is often referred to as the donor star. The infalling matter, which is usually rich in hydrogen, forms in most cases an accretion disc around the white dwarf. Strong UV and X-ray emission is often seen from the accretion disc, powered by the loss of gravitational potential energy from the infalling material. Material at the inner edge of disc falls onto the surface of the white dwarf primary. A classical nova outburst occurs when the density and temperature at the bottom of the accumulated hydrogen layer rise high enough to ignite runaway hydrogen fusion reactions, which rapidly convert the hydrogen layer to helium. If the accretion process continues long enough to bring the white dwarf close to the Chandrasekhar limit, the increasing interior density may ignite runaway carbon fusion and trigger a Type Ia supernova explosion, which would completely destroy the white dwarf. The accretion disc may be prone to an instability leading to dwarf nova outbursts, when the outer portion of the disc changes from a cool, dull mode to a hotter, brighter mode for a time, before reverting to the cool mode. Dwarf novae can recur on a timescale of days to decades.

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