Neutrino luminosity and the energy spectrum of a nova outburst

The nova outburst can produce a large number of neutrinos, whether it is the nuclear reaction process during the explosion or the shock wave acceleration proton process. We study the low-energy nuclear and thermal neutrino luminosity of novae with CO white dwarf (WD) mass ranging from 0.6 to $1.1{M}_{\ensuremath{\bigodot}}$ with different accretion rates $\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{M}$, core temperatures $({T}_{\mathrm{C}})$, and mixing degrees. We find that, during the accretion phase, low-energy neutrinos are mainly produced by pp chains and plasma decay, and photon luminosity is greater than low-energy nuclear and thermal neutrino luminosity. During the thermonuclear runaway (TNR) phase, low-energy neutrinos are mainly produced by the CNO cycle and photon-neutrino interaction, and the low-energy nuclear and thermal neutrino luminosity far exceeds the photon luminosity. We find that the more massive the WD, the shorter the cycle time and the higher the low-energy nuclear neutrino luminosity. The higher the accretion rate, the lower the low-energy nuclear neutrino luminosity. If the accretion mixing effect is not taken into account, the outburst interval becomes longer, and the low-energy nuclear neutrino luminosity will be increased. For the cooler nova model $({T}_{\mathrm{C}}=1\ifmmode\times\else\texttimes\fi{}{10}^{7}\text{ }\text{ }\mathrm{K})$, the low-energy nuclear neutrino luminosity will be lower during the accretion phase and higher at the TNR. We also predict the neutrino luminosity and energy spectrum of the upcoming recurrent nova T Coronae Borealis (T CrB). We estimate that the next T CrB outburst has a low-energy nuclear neutrino peak luminosity of $2.7\ifmmode\times\else\texttimes\fi{}{10}^{8}{\mathrm{L}}_{\ensuremath{\nu},\ensuremath{\bigodot}}$ and a low-energy nuclear neutrino outburst duration of 88 days. In addition, we predict that the high-energy hadronic neutrino flux produced by T CrB nova cannot be observed by the current-generation IceCube.