A Type II supernova that erupted in the Large Magellanic Cloud on 1987 February 24, and which reached a maximum apparent magnitude of 2.8 in mid-May of that year. It was the first supernova to reach naked-eye brightness since 1604, and remained visible to the naked eye until the end of 1987. Its progenitor was Sanduleak −69° 202, a blue supergiant, contrary to predictions that a Type II supernova arises from a massive, red supergiant. A burst of neutrinos from the supernova was detected on Earth. Gamma-ray lines from the radioactive decay of ⁵⁶Co to ⁵⁶Fe were observed, confirming that heavy elements are produced in supernovae. A ring of gas about 1 l.y. in diameter observed around the star is believed to have been shed in an earlier red supergiant phase.

http://hubblesite.org/news_release/news/2017-08/91-astronomical