SMOKE RINGS AROUND SUPERNOVA 1987A

Detailed observations of the [O III]5007 Angstrom emission from the el liptical rings around SN 1987A suggest a model wherein the two feint, outer rings are due to emission from two circular toroids moving outwa rds (at less than or equal to 25 km s(-1)) along a,bipolar cone centre d on the site of the supernova. The brighter, central ring is expandin g radially outward at 8.3 km s(-1). The rings must have been created s imilar to 2 - 3 x 10(4) years before the supernova explosion and are t hought to be a consequence of the interaction of stellar winds emanati ng from the progenitor system during the final stages of its evolution to a supernova.