The intrinsic-heat generation has long been known in the Jovian planets. The current view ascribes its origin to the gradual release of primordial heat produced at the birth of these planets. This scenario, however, fails to explain coherently the magnitude of the excess heat in each planet, other than Jupiter, and must invoke some additional sources. We point out the possibility that this heat, or at least a part of it, could be attributed to proton decay which is catalyzed by grand-unified magnetic monopoles (Rubakov effect) captured in the planets. The monopole flux required for this is of order ∼1×${10}^{\mathrm{-}23}$ ${\mathrm{cm}}^{\mathrm{-}2}$ ${\mathrm{sr}}^{\mathrm{-}1}$ ${\sec }^{\mathrm{-}1}$, which is smaller than the limit on the cosmic monopole flux so far obtained. We also show that if the monopole flux is of this order the monopole captured in the Sun gives rise to the neutrino flux (〈$E_{\nu }$〉≃35 MeV) which should be detectable in the underground experiment searching for nucleon decays currently in progress.

• Received 26 June 1984

DOI:https://doi.org/10.1103/PhysRevD.32.2586