A Type Ia supernova is a type of supernova that occurs in binary systems in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf.
G299 Type Ia supernova remnant.
An accretion disc forms around a compact body (such as a white dwarf) stripping gas from a companion giant star. NASA image
Supercomputer simulation of the explosion phase of the deflagration-to-detonation model of supernova formation.
Supernova remnant N103B taken by the Hubble Space Telescope.
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to Earth's. A white dwarf's low luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Luyten in 1922.
Artist's impression of debris around a white dwarf
Comet falling into white dwarf (artist's impression)
Illustration of rocky debris around a white dwarf
Cocoon of a new white dwarf in the centre of NGC 2440