Depicts: SN1987A Copyright: Jason Pun (NOAO) and SINS Collaboration Show in archive: true
The ring formed 30,000 years before the star exploded and so is a fossil
record of the final stages of the star's existence. The light from the
supernova heated the gas in the ring so that it now glows at temperatures from
5,000 to 25,000 degrees Kelvin.