RING NEBULA AND BIPOLAR OUTFLOWS ASSOCIATED WITH THE B1.5 SUPERGIANT SHER-25 IN NGC-3603

We have identified a ring-shaped emission-line nebula and a possible b ipolar outflow centered on the B1.5 supergiant Sher 25 in the Galactic giant H II region NGC 3603 (distance 6 kpc). The clumpy ring around S her 25 appears to be tilted by 64 degrees against the plane of the sky . Its semimajor axis (position angle approximate to 165 degrees) is 6. 9'' long, which corresponds to a ring diameter of 0.4 pc. The bipolar outflow filaments, presumably located above and below the ring plane o n either side of Sher 25, show a separation of approximate to 0.5 pc f rom the central star. High-resolution spectra show that the ring has a systemic velocity of V-LSR = +19 km s(-1) and a deprojected expansion velocity of 20 km s(-1), and that one of the bipolar filaments has an outflow speed of similar to 83 km s(-1). The spectra also show a high [N II]/H alpha ratio, suggestive of strong N enrichment. Sher 25 must be an evolved blue supergiant (BSG) past the red supergiant (RSG) sta ge. We find that the ratio of equatorial to polar mass-loss rate durin g the RSG phase was approximate to 16. We discuss the results in the f ramework of RSG-BSG wind evolutionary models. We compare Sher 25 to th e progenitor of SN 1987A, which it resembles in many aspects.