|NGC 3583 [Credit: ESA/Hubble & NASA, A. Riess et al.]
There are a few ways that supernovae can form. In the case of these two supernovae, the explosions evolved from two independent binary star systems in which the stellar remnant of a Sun-like star, known as a white dwarf, was collecting material from its companion star. Feeding off of its partner, the white dwarf gorged on the material until it reached a maximum mass. At this point, the star collapsed inward before exploding outward in a brilliant supernova.