SUPERNOVA 1987A - A COLD, DUSTY AND RUSTY SUPERNOVA

We have modelled the near-infrared emission from forbidden lines of singly ionized iron in the ejecta of Supernova 1987 A. We find that as late as 1989 February, relatively high excitation transitions such as those arising from the a4F-a2G multiplet at 7150 angstrom are surprisingly strong. The inferred temperature and electron density imply a mass of Fe+ of order 10-(3)M.. We do not find evidence for strong emission by neutral or doubly ionized iron. Given that 0.07 M. of iron are believed to be present in the ejecta of SN 1987A, our results suggest that the bulk of the iron is unable to emit in our wavelength range.