Supernova
A supernova is the explosive death of a star, during which it rapidly ejects most of its mass in a brilliant burst of light. In core‑collapse supernovae (Types Ib, Ic, II), massive stars (≥ 8 solar masses) exhaust their nuclear fuel, collapse under gravity, and explode. In Type Ia supernovae, a white dwarf in a binary system undergoes runaway fusion after accreting mass. These events deliver heavy elements into space, leave behind neutron stars or black holes, and power typical shock‑front supernova remnants.
Source: heasarc.gsfc.nasa.gov
APODs including "Supernova"
Four Supernova Remnants
28/07/2006
These four panels show x-ray images of expanding cosmic debris clouds, tens of light-years across, in nearby galaxy the Large Magellanic Cloud. The supernova remnants (SNRs) are the results of two types of stellar explosions and are arranged in order of apparent age or the time since light from the initial explosion first reached planet Earth. Clockwise starting at the upper left are remnants aged 600 years, 1,500 years, 10,000 years and 13,000 years. The first three result from a Type Ia explosion - the destruction of a white dwarf star by a thermonuclear blast triggered by mass accreted from a stellar companion. The fourth (lower left) is a Type II explosion - triggered by the final collapse of the core of a massive star. A neutron star, the remnant of the collapsed core, lies at its center.