dipper@utastro.UUCP (Debbie Byrd) (06/06/85)
This is the anniversary of a star caught in the act of blowing up. More -- after this. June 6 A Supernova Caught in the Act Near the end of their lives, most stars expand to become great red giants -- larger in diameter than our solar system. Some of these stars later may erupt as supernovae -- increasing in brightness by millions of times. A handful of supernovae have been observed in our Milky Way galaxy. But many supernovae are seen in other galaxies. They generally aren't noticed until the explosion has reached a maximum in intensity, and the star is beginning to fade. But, on today's date two years ago, astronomers got lucky -- they caught a supernova in the act of erupting. On June 6, 1983, an astronomer observing in Chile was looking at photographs of the distant galaxy NGC 4699. She noticed a star in that galaxy that was 300 times as bright as it should be. It was a supernova -- not fading -- but getting brighter -- nearly two weeks before maximum light. The supernova was dubbed 1983k, for its place in the yearly sequence of discovery of such objects. It's the first supernova to give astronomers a chance to watch the process of a stellar explosion. The astronomers believe their data show evidence for a shock wave beginning deep within the star -- rising to the surface -- then blowing the star's outer surface entirely off. The discovery of this supernova is important, since supernovae lead to the release of the heavy chemical elements into space. Such elements -- forged inside stars -- are the raw materials for new stars, planets -- and life itself. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin