Estimation of the probable size of the lunar core based on geophysical and geochemical data

Abstract

This study is devoted to estimations of the possible sizes of the lunar core, which were obtained with two independent approaches based on solving the inverse problem of determining the internal structure and composition of the Moon. For calculations Monte Carlo method was used taking into account geophysical and geochemical constraints on the models. In the first method, the inverse problem was solved for two different temperature models (“cold” and “hot”). In the second method, two different models of the bulk composition of the lunar mantle (Earthlike and enriched in Al2O3) were considered. Both approaches led to similar values for the radius of the lunar core. It was found that the radii of Fe-S core are in the range of 50-350 km with the most probable value of about 300 km (∼ 1% of the mass of the Moon) and are rather weakly dependent on the thermal regime and chemical composition of the lunar mantle.