MANTLE DENSITY AND CORE SIZE OF THE MOON

A five-layer model of the Moon, comprising the crust; the upper, middl e, and lower mantle; and the core, is used to estimate the size of the core by correlating the calculated values of lunar mass and moment of inertia with experimental data. The maximum core diameters are evalua ted at 460 km (for an iron core) and 685 km (for an iron sulfide core) , corresponding to 4.3 and 8.2% of the Moon's mass, respectively, The probable size of an iron sulfide core is 300-500 km. Models of the Moo n without a core (with a radius close to zero) lead to a lower-mantle density of p greater than or equal to 3.47 g/cm(3). The density distri bution in the lunar mantle is constrained by the density and size of t he core and crustal density and thickness.