THE ENVIRONMENTS OF SUPERNOVAE IN ARCHIVAL HUBBLE-SPACE-TELESCOPE IMAGES

We have examined the immediate environments of several supernovae usin g archival prerefurbishment Hubble Space Telescope images to search fo r clues to the nature of the progenitor stars. For the Type II superno va 1968L in M83 the colors of nearby star clusters indicate ages of le ss than or similar to 6-7X10(6) yr, implying an initial mass of greate r than or similar to 25-30 M. for the progenitor, if it formed coevall y with the clusters. This limit is higher than expected for a typical Type II progenitor, and may indicate that the supernova progenitor for med earlier than the nearby clusters. Images of M51 obtained prior to the explosion of the Type Ic SN 1994I are used to derive an upper limi t to the absolute magnitude of the progenitor star of M(V)>-7.3+/-0.7 mag. This limit is unfortunately not sufficiently restrictive to const rain models of Type Ic supernovae. We also discuss images containing t he sites of supernovae 1991N (Type Ic), 1992bd (Type II), and several Type Ia supernovae. As higher-quality post-refurbishment data become a vailable in the archive, we expect substantial improvement in our unde rstanding of individual supernova environments. (C) 1996 American Astr onomical Society.