Optical spectra of the ejecta of SN 1987A taken at the AAT now cover seven years of evolution. In recent years, SN 1987A has been in a phase known as freeze-out. The timescales for recombination have exceeded those of energy deposition, and the ionisation structure has become fixed. During this phase, cooling is slow and the optical spectrum has been extremely stable. Our latest spectrum, however, shows significant change. [FeI] and [FeII] emission from iron-rich clumps has dominated the optical emission from the supernova over the last four years. All the [FeII] features have disappeared in our latest spectrum from December 1993 and model fits of [FeI] features indicate that these clumps have cooled to the critical temperature of 1000 K. They may be entering a phase of rapid cooling known as the infrared catastrophe. In addition, emission at high velocities has strengthened, in line with the predictions of freeze-out. SN 1987A may be entering a new, and previously unobserved, phase in supernova evolution.

We construct stellar evolution models until core collapse using KEPLER (Woosley & Heger (2007)) to reproduce the observed signatures of the blue supergiant (BSG) progenitor of SN 1987A. This is based on the binary merger scenario proposed by Podsiadlowski (1992) and Ivanova et al. (2002). Various combinations of initial parameters for the binary components (M1=16–18 M⊙ and M2=5–10 M⊙) and their merging, successfully match the He, N/C and N/O ratios, along with the luminosity and effective temperature of the progenitor. Most of our models end their lives as BSGs. Thus we may be able to explain the origin of all Type IIP SNe that resemble SN 1987A through such mergers. We are currently working on the light curves and nuclear yields from the explosion of these models to compare them SN 1987A.

SNR 1987A is the expanding remnant from the brightest supernova since the invention of the telescope. The remnant has been monitored extensively in the radio at variety of wavelengths and provides a wealth of data on which to base a simulation. Questions to be answered include estimating the efficiency of particle acceleration at shock fronts, determining the cause of the one-sided radio morphology for SNR 1987A and investigating the gas properties of the pre-supernova environment. We attempt to address these questions using a fully three-dimensional model of SNR 1987A.