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"
Galaxy and Cluster Create Four Images of Distant Supernova
09/03/2015
What are the unusual spots surrounding that galaxy? They are all images of the same supernova. For the first time, a single supernova explosion has been seen split into multiple images by the gravitational lens deflections of intervening masses. In this case the masses are a large galaxy and its home galaxy cluster. The featured image was captured last November by the Earth-orbiting Hubble Space Telescope. The yellow-hued quadruply-imaged Supernova Refsdal occurred in the early universe far behind the cluster. Measuring the locations and time-delays between the supernova images should allow astrophysicists to recover the amount of dark matter in the galaxy and cluster. With patience and luck, a fifth image of the supernova will also be recovered nearby in the next few years. Astrophysicists: Browse 1,000+ codes in the Astrophysics Source Code Library