Emission of Photoneutrinos and Pair Annihilation Neutrinos from Stars

Field-theoretic calculations of the cross sections for the photoneutrino process, γ+e^-→e^-+ν+ν, and the pair annihilation process, e⁺+e^-→ν+ν, are performed in order to obtain the neutrino luminosity of very hot stars (Tc5×10⁸^∘K). The energy loss rate which is obtained for the latter process is sufficient to determine the rate of evolution of the stellar core when Tc2×10⁹^∘K.