Lunar antineutrinos and heat: Fluxes from primordial radioactivity

We present estimates for the fluxes of heat and antineutrinos due to primordial radioactivity within the moon. We use a radial density profile, specifying an inner core and a model-averaged crust. The 1^∘ by 1^∘ gridded crust data draw on global maps from spacecraft missions. Thickness, density, and elevation come from measurements of the gravitational field. Thorium, uranium, and potassium abundances come from measurements of the gamma ray intensity. Assuming no vertical variation of the crustal abundances predicts $302$ GW of radiogenic heating. Accepting a heat flux of $5$ mWm⁻² from the mantle plus low viscosity zone both with Th/U3.7 and K/U2000 tallies an additional $185$ GW of radiogenic heating. The corresponding antineutrino fluxes from the average crust and the mantle plus low viscosity zone are 2.02×10⁶ cm⁻²s⁻¹ and 6.40×10⁵ cm⁻²s⁻¹, respectively. Subsurface variations of thorium, uranium, and potassium abundances in the crust are a potentially large and not yet assessed source of uncertainty. The uncertainties reported with the radial density profile contribute ±1.4×10³ cm⁻²s⁻¹ and ±0.6 GW ($<1$%) to the estimates of antineutrino flux and radiogenic heating, respectively, from the mantle plus low viscosity zone.