Fig. 2. a The optical depth for the -ray photon with energy eV in the soft radiation of a massive star, as a function of the angle of photon injection . The star has the radius cm and the surface temperature K. The specific curves correspond to different distances of injection of the primary photon from the center of a star , and . b The optical depth for the -ray photons, as a function of their energy , which are injected at the distance . Specific curves correspond to different angles of photon injection .