Lunar antineutrinos and heat: fluxes from primordial radioactivity

TL;DR

This paper estimates lunar heat flux and antineutrino fluxes from primordial radioactivity, providing new quantitative predictions based on lunar composition models and remote sensing data.

Contribution

It introduces a detailed lunar model for radiogenic heat and antineutrino fluxes, integrating lunar composition and gravitational data for the first time.

Findings

Radiogenic heating of 311±37 GW in the Moon.

Surface heat flux of 8.19±0.97 mW/m².

Antineutrino flux of (1.83±0.32)×10^6 cm⁻²s⁻¹.

Abstract

We estimate 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. Thickness, density, and elevation of the lunar crust are from remote measurements of the gravitational field. Lateral and vertical variations of thorium, uranium, and potassium abundances in the crust follow from a prediction of the lunar bulk chemical composition. We constrain the total contents of thorium, uranium, and potassium using estimates for the earth's primitive mantle. These contents produce $311\pm37$ GW of radiogenic heating and a surface-averaged heat flux of $8.19\pm0.97$ mW/m$^2$. Our lunar model estimates an antineutrino flux of $(1.83\pm0.32)\times10^6$ cm$^{-2}$s$^{-1}$ and an antineutrino inverse beta decay rate of $5.8\pm1.0$ per $10^{32}$ free proton targets per year, both averaged over the surface.