Ultraviolet views and spectroscopic clues

Abstract

IUE observations of SN 1987A obtained on days 60-260 of 1987 are presented graphically and characterized in detail. Particular attention is given to the complex changes in the early spectra, the domination of the energy distribution by line blanketing after an initial cooling period, and the spectra of the survivors (stars 2 and 3 of Sk -69 deg 202). The later emergence of narrow UV emission lines is attributed to photoionization of N-rich gas in a circumstellar shell, probably ejected from the SN 1987A progenitor (star 1 of Sk -69 deg 202) during its red supergiant phase.