Emission of Photoneutrinos and Pair Annihilation Neutrinos from Stars

Abstract

Field-theoretic calculations of the cross sections for the photoneutrino process, $\ensuremath{\gamma}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}+\ensuremath{\nu}+\overline{\ensuremath{\nu}}$, and the pair annihilation process, ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\nu}+\overline{\ensuremath{\nu}}$, are performed in order to obtain the neutrino luminosity of very hot stars (${T}_{c}\ensuremath{\gtrsim}5\ifmmode\times\else\texttimes\fi{}{10}^{8}\ifmmode^\circ\else\textdegree\fi{}$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 ${T}_{c}\ensuremath{\gtrsim}2\ifmmode\times\else\texttimes\fi{}{10}^{9}\ifmmode^\circ\else\textdegree\fi{}$K.