Symbiotic novae are slow irregular eruptivevariable stars with very slownova-like outbursts with an amplitude of between 9 and 11magnitudes. The symbiotic nova remains at maximum for one or a few decades, and then declines towards its originalluminosity. Variables of this type aredouble star systems with onered giant, which probably is aMira variable,^[1] and one a hotcompact object (usually awhite dwarf), with markedly contrasting spectra and whose proximity and mass characteristics indicate it as a symbiotic star. They are divided into D-type (dusty) or S-type (stellar), depending on whether the giant is a Mira variable or not.^[2]

The red giant fills itsRoche lobe so that matter is transferred to the white dwarf and accumulates until a nova-like outburst occurs, caused by ignition ofthermonuclear fusion. The temperature at maximum is estimated to rise up to 200,000 K, similar to the energy source of novae, but dissimilar to thedwarf novae. The slow luminosity increase would then be simply due to time needed for growth of the ionization front in the outburst.^[3]

It is believed that the white dwarf component of a symbiotic nova remains below theChandrasekhar limit, so that it remains a white dwarf after its outburst.^[3]

One example of a symbiotic nova isV1016 Cygni, whose outburst in 1971–2007 clearly indicated a thermonuclear explosion.^[4] Other examples areHM Sagittae andRR Telescopii.^[1]

• Dwarf nova – Cataclysmic variable star, consisting of a close binary star system
• Nova – Nuclear explosion in a white dwarf star
• Supernova – Astrophysical phenomenon

• SEAL P. (1990). "A discussion on the classification and evolution of symbiotic stars".Astrophys. Space Sci.174 (2):321–325.Bibcode:1990Ap&SS.174..321S.doi:10.1007/BF00642518.S2CID 121276497.
• Friedjung, Michael (1993). "Models of symbiotic stars".NASA.507:647–662.Bibcode:1993NASSP.507..647F.

• Symbiotic novae

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