The multi-institutional Palomar Transient Factory (PTF) team has released the first-ever direct observations of a Type 1a supernova progenitor system.
Astronomers have collected evidence indicating that the progenitor system of a Type 1a supernova, called PTF 11kx, contains a red giant star. This artist's conception shows a binary star system that produces recurrent novae, and ultimately, the supernova PTF 11kx. A red giant star (foreground) loses some of its outer layers though a stellar wind, and some of it forms a disk around a companion white dwarf star. This material falls onto the white dwarf, causing it to experience periodic nova eruptions every few decades. When the mass builds up to the near the ultimate limit a white dwarf star can take, it explodes as a Type Ia supernova, destroying the white dwarf.
(Animation credit: Romano Corradi and the Instituto de Astrofísica de Canarias)