Late-time spectroscopy of two supernovas - The type II 1980K and the type V 1986J

Abstract

Late-time spectra of the type II SN 1980K and the type V SN 1986J are presented. The SN 1980K spectrum is similar to one obtained nearly a year earlier by Fesen and Becker (1990) except that the Fe II multiplet 42 lines have changed relative strengths. Supernova 1986J shows a spectrum qualitatively similar to, but much fainter than, that observed earlier by Rupen et al. (1987). Its H-alpha flux declines exponentially, but not at the rate of any radioactive element expected to be formed in a supernova. Both of these objects are much brighter than expected if radioactive decay of Co-56 provided the energy source for their late-time luminosity. The optical and radio data available for SN 1986J indicates that it was probably not a true supernova but instead the outburst of a luminous blue variable similar to Eta Car. 30 refs.