THE 3-RING STRUCTURE OF SUPERNOVA-1987A

The current scenario for the complex less than or equal to 3-arcsec st ructures surrounding SN 1987A is that they result from the emission of a thin shell of matter surrounding the supernova, illuminated by the initial extreme-ultraviolet flash from the explosion of the progenitor . Before the Hubble Space Telescope (HST) the two ring-shaped loops, s imilar to 3 arcsec in size, clearly visible in all images taken more t han two years after the explosion in the UV-to-optical continuum, were interpreted as limb brightening of the outer parts of this nebula. Ho wever, the 1994 HST images show that these structures are actually rin g-like. Accordingly, we propose a different explanation for these two rings: allowing for the presence of a shell, we suggest that the rings are part of this shell brightened by the interaction of the double be am of relativistic particles emitted from a young pulsar formed after the explosion.