ASTRONOMY: supernova

Supernova. This image is 600 x 445 pixels; the original measures 4,015 x 2,975 pixels.

Supernovae result from the explosive death of a star and are classified as two types. Type Ia supernovae occur in binary star systems in which gas from one star falls onto a white dwarf with a mass close to the Chandrasekhar critical mass and causes it to explode (like in this image). The explosion is caused by the ignition of runaway thermo-nuclear reactions under degenerate matter conditions. Type II supernovae occur in stars at least ten times more massive than our Sun, which suffer runaway thermo-nuclear reactions at the end of their lives, leading to explosions. Such explosions can be either total (no solid remnant) or may leave behind a rapidly spinning neutron star (a pulsar) or a black hole.