The Progenitor of SN 1987A

Abstract

Supernova 1987A in the Large Magellanic Cloud was the first naked-eye supernova since Kepler’s supernova in 1604. Neutrino detections from the event dramatically confirmed the long-held belief that this type of supernova is triggered by the final collapse of the core of a massive star, but in many other respects it was a very unusual, even anomalous event. The progenitor was a blue supergiant instead of a red supergiant, as had been predicted theoretically, and the system was surrounded by a spectacular triple-ring nebula that consists of material that was ejected only 20,000 years before the explosion. This chapter will discuss the mystery of the supernova progenitor and how all the evidence points toward a dramatic event that occurred some 20,000 years ago, the merger of two massive stars and how future observations will further help to prove or refute the current picture.