Abstract
THE recent discovery of large mass concentrations (mascons) beneath the lunar circular maria from Lunar Orbiter tracking data1 raises the question of whether mascons can influence the dynamical figure of the Moon. A convenient way to describe the lunar figure is in terms of the moments of inertia about the three principal axes, where C is about the axis of rotation, A is about an axis along the lines of centres of the Earth and the Moon, and B is about an axis tangent to the orbit. It is well known from observation that C>B>A and that their differences exceed by about an order of magnitude the predicted values from hydrostatic equilibrium and tidal distortion. There is a one-to-one correspondence between large mascons and circular maria1. But the circular maria have a non-uniform distribution over the lunar surface, with a tendency for locations toward the equator and toward the sub-Earth point. These locations are in the correct sense to suggest that mascons are responsible for the non-equilibrium contribution to the inequality C>B>A.
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O'LEARY, B. Influence of Lunar Mascons on its Dynamical Figure. Nature 220, 1309 (1968). https://doi.org/10.1038/2201309a0
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DOI: https://doi.org/10.1038/2201309a0
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