THE PECULIAR TYPE-II SN1987B IN NGC-5850

Nine photometric and five spectroscopic observations of the peculiar T ype II supernova SN1987B in NGC 5850 are presented. The light curve is different from any of the typical supernova light curves. The light c urve falls as slowly as a Type IIP light curve for similar to 50 days, then steepens considerably, in contrast to the spectroscopically simi lar object SN1988Z. Both SN1987B and SN1988Z have been considered as r epresentative of ''Type IIn'' supernovae, those supernovae that show c ircumstellar signatures in their spectra. The spectra of SN1987B show weak hydrogen emission lines with a narrow core (FWZI similar to 1000 km s(-1)) and weak, low-contrast emission lines of hydrogen with a FWZ I of similar to 8000 km s(-1). Both photometric and spectroscopic evid ence suggests SN1987B had a low-mass envelope. (C) 1996 American Astro nomical Society.