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"
Rampaging Fronts of the Veil Nebula
07/03/1996
A supernova explosion of a high-mass star results in fast moving blast waves. At the front of the waves shown above, ionized gas in the Veil Supernova Remnant rushes out from the explosion, sweeps up material, and breaks up many atoms into constituent ions and electrons. Observations with the Hubble Space Telescope in 1993 indicate that the blue shock wave was catapult away from the stellar explosion after the red shock wave and has yet to catch up to it in some regions. The Veil supernova remnant's has a very large angular size - six times the diameter of the full moon - and different parts of it are known as the "Cygnus Loop" and catalog numbers NGC 6960, NGC 6979, NGC 6992, and NGC 6995. Information: The Scale of the Universe Debate in April 1996