Emergence of hard radiation from the envelpe and optical luminosity of supernova 1987A.

Deviations of the light curve of SN 1987A from the exponential law due to the escape of hard radiation from the envelope and emission from the central young pulsar are calculated. The early appearance of X-ray flux from the supernova is explained by the strong mixing of radioactive cobalt over the envelope. The radial dependence of the heating rate of envelope matter due to the interaction with hard radiation from radioactive cobalt is determined.