Symbiotic novae

Abstract: (Invited Review) According to modern definition, a symbiotic nova is an otherwise normal nova (i.e. powered by explosive thermonuclear burning) that erupts within a symbiotic star, which is a binary where a WD accretes from a cool giant companion. Guided primarily by the very well observed eruptions of RS Oph in 2006 and 2021, and that of V407 Cyg in 2010, we investigate the main multi-wavelength properties of symbiotic novae and their relation to classical novae, and propose a 3D model structure that identifies the emitting source location for hard and supersoft X-rays, radio syncrothron and thermal, permitted and forbidden emission lines. Very few symbiotic novae are known in the Galaxy, and we compile a revised catalog based on firm astrometric identification. The exciting prospect of an imminent new outburst of T CrB is also discussed.