Supernova 1987a: NASA's plans for x-ray and gamma-ray observations

Supernova 1987a is the brightest and nearest stellar explosion that has occurred in the last three hundred years. As of this writing its apparent magnitude in visible light is m=3.0 (the human eye can see up to m=5 or 6). It is located in the Large Magellanic Cloud (LMC), our nearest neighbor galaxy at a distance of 50 000 kpc (1 pc approx. = 3 light years approx. = 3 X 10/sup 18/cm). Its present brightness in the visible range is more than 100 million times that of the sun. The supernova is expected to produce emission over essentially the entire electromagnetic spectrum. Thus far it has been detected in the radio, IR, visible, and UV bands. X-rays and gamma-rays, although not yet detected, are expected to eventually be seen and to contain some of the most exciting new information on this phenomenon. This note deals with the planned NASA observations in these high-energy wavelength bands and their scientific importance.