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"
Eta Carinae in X-Rays
11/10/1999
Carinae is the one of the most luminous star systems in our Galaxy, radiating millions of times more power than our Sun. Eta Carinae is also one of the strangest star systems known, brightening and fading greatly since the early 1800s. Recently, the Chandra Observatory observed Eta Carinae in X-ray light, adding even more unanticipated pieces to this enigmatic puzzle. Pictured above, a horseshoe-shaped outer ring about two light-years across has been discovered surrounding a hot core measuring three light-months across. One thing appears likely: these structures were caused by collisions involving matter expelled from the center at supersonic speeds. Speculation continues that Eta Carinae will be seen to undergo a supernova explosion sometime in the next thousand years.