HUBBLE-SPACE-TELESCOPE OBSERVATIONS OF PLANETARY-NEBULAE IN THE MAGELLANIC CLOUDS .1. THE EXTREME TYPE-I SMP-83 WS-35

We have obtained Hubble Space Telescope Planetary Camera images in bot h the Halpha and the [O III] lambda5007 emission lines of the planetar y nebula SMP 83 alias WS35, alias N66 in the Large Magellanic Cloud. B y combining these results with optical and UV spectrophotometry, absol ute flux measurements, and dynamical and density information, we have been able to construct a fully self-consistent nebular model. This pro ves that SMP 83 is an extremely massive type I object having a central star having an effective temperature of 170,000 K and a luminosity of nearly 3 x 10(4) L.. The core mass is estimated in the range 1.0-1.2 M., for which the main-sequence mass was greater than approximately 6 M.. The nebular abundances are higher than the average for the LMC and show evidence for hot-bottom burning.