How long does a supernova last?
There is no single answer to your question. In a sense, the explosion itself is over within a matter of seconds. But the envelope of the dying star is expelled with such speed that, when it ploughs into the interstellar gas, it is heated to millions of degrees and remain bright in X-rays for tens of thousands of years. In the visual light, how long you can track supernovae depends on their distance. Supernova 1987A in the Large Magellanic Cloud (which is relatively nearby as these things go) is still being followed from the ground and from the Hubble Space Telescope: http://oposite.stsci.edu/pubinfo/pr/1998/08/ Best wishes, Koji Mukai for Ask a High-Energy Astronomer QUESTION: When a star of adequate mass ceases to have enough fusion to support its self, collapeses and goes supernovae just exactly WHERE does the energy come from that causes the explosion? The answer provided on your site simply stated that the star collaped and enery was produced. So where does it come from? ANSWER: Th
