High-energy Neutrino Predictions for T Coronae Borealis: Probing Particle Acceleration in Novae

Abstract The MAGIC detection of near-TeV gamma rays from the 2021 RS Oph (2.45 kpc) outburst has established recurrent novae as TeV particle accelerators. However, the origin of this emission (hadronic versus leptonic) remains unclear due to the lack of coincident neutrinos detected by IceCube. The upcoming outburst of the much closer T Coronae Borealis (T CrB; ∼0.887 kpc) offers a unique opportunity to detect these rare nova neutrinos. Here we present the first comparative analysis of the hadronic secondary fluxes expected from the upcoming T CrB outburst and evaluate their detectability across major observatories, considering two proton-acceleration mechanisms: (i) an external shock (ES) at ∼10 13 cm and (ii) magnetic reconnection (MR) near the white dwarf surface at ∼10 9 cm. While the benchmark ES model predicts a gamma-ray flux detectable by current facilities, its corresponding neutrino flux largely remains undetectable. In contrast, the MR scenario generates a robust neutrino flux within the reach of IceCube and KM3NeT. Importantly, as the MR-produced gamma rays are absorbed, the escaping MR neutrinos will arrive hours before any ES-origin signals. This distinct temporal separation can create a powerful phenomenological signature to disentangle the nova acceleration physics.