| Themes > Science > Astronomy > The Stars > Kinds of Stars > Supernova 1987A |
In 1987 a supernova (designated SN1987A by astronomers) was observed in a nearby galaxy called the Large Magellanic Cloud. Detection of the NeutrinosThis was the first "nearby" supernova in the last 3 centuries, and for the first time astronomers not only observed the light show, but also detected 19 of the elusive neutrinos (the detectors observed electron anti-neutrinos, to be more precise) produced by the collapse of the star's core. The burst of neutrinos preceded the first sighting of the supernova's light by about 3 hours, in agreement with the expectations of current supernova theory. These observations are rather conclusive evidence for the correctness of the core collapse mechanism, since it would be difficult to produce the observed neutrino burst by any other means.It is estimated that for an instant in 1987 on the earth the neutrino luminosity of SN1987A was as large as the visible-light luminosity of the entire universe. The Mysterious RingsThe adjacent figure is a 1994 Hubble Space Telescope image of the region surrounding SN1987A. The supernova is in the center. The two bright stars are just in the field of view and are not associated with the supernova. The bright yellow ring is thought to be gas and dust heated by the supernova (the expanding shell of the explosion itself that will produce the supernova remnant is still too small to be seen in this photograph). The two large rings are not yet completely understood, though they appear to be associated with the supernova. It is rather certain that the rings result from something that the star did before it became a supernova, probably associated with the strong stellar winds expected in such stars that emit large amounts of matter into space. Click here for one of several ideas about the source of the mysterious rings. |
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