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We consider the γ+p→ n + ν + e+reaction and his implication in stellar evolution. Besides the neutrino emission, we call attention also on the neutron production; it seems likely that this reaction might have some importance in the superdense stars.

IN a previous communication1we reported some evaluations of the neutrino energy density in the universe taking into account the e++ e-? ? + ?¯ process in the pre-supernova stage of the stars. We found that this energy density may be higher than the energy density of the matter. Here we present a similar evaluation on the basis of the Mannino2hypothesis regarding the star-like objects. It is known that the optical power of these objects is about 1046–1048ergs/sec (ref. 3). According to Mannino2, this may be due to supernova explosions of as many as 4,000 a year. During the exploding stage the temperature of the stars goes up to 109–1010° K and the star begins to emit neutrino antineutrino pairs through annihilation of electron-positron pairs which at this high temperature are in equilibrium with the photons. The neutrino emission is of the same order and even higher of the photon emission4. Thus we can safely assume that the star-like sources emit 1048ergs/sec as neutrino power. Because the energies of these neutrinos are of the order of a MeV, we have an emission of ~1054?/sec/star-like source. (We can obtain these figures also supposing that each supernova inside the star-like object emits ~1045ergs/sec as neutrino power; since we have 10-4supernovse/sec, and since the process goes on for about 200 days2, this is the same as saying that at each time we have 10-4.107= 103supernova in the whole star-like, which means an emission of 1045.103= 1048ergs/sec from the star-like sources.)