The freeze-out phase of SN 1987A - Implications for the light curve

After ~800 days, time-dependent effects due to long recombination and cooling times lead to a frozen-in structure of the ejecta of SN 1987A. The result is a higher bolometric luminosity, compared to models where the emitted luminosity is equal to the instantaneous energy input. Good agreement with the observed light curve of SN 1987A is obtained with an initial ⁵7Ni/⁵6Ni ratio 2 times the solar ⁵7Fe/⁵6Fe ratio, while steady state models require a factor of 2 more. Consistency with both the ⁵7Co mass from IR line observations, X-ray, and γ-ray observations, and from models of the nucleosynthesis can thus be obtained.