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Near/Far Side Asymmetry in the Tidally Heated Moon

Research paper by Alice C. Quillen, Larkin Martini, Miki Nakajima

Indexed on: 24 Oct '18Published on: 24 Oct '18Published in: arXiv - Astrophysics - Earth and Planetary Astrophysics



Abstract

Using viscoelastic mass spring model simulations to track heat distribution inside a tidally perturbed body, we measure the asymmetry of heating in the crust of a spin synchronous Moon in eccentric orbit about the Earth. With the Moon within a few Earth radii of the Earth, we find that tidal heating per unit area in a lunar crustal shell is asymmetric due to the octupole order moment in the Earth's tidal field and is 10 to 20\% higher on its near side than on its far side. Tidal heating reduces the crustal basal heat flux and the rate of magma ocean crystallization. Assuming that the local crustal growth rate depends on the local basal heat flux and the distribution of tidal heating in latitude and longitude, a heat conductivity model illustrates that a moderately asymmetric and growing lunar crust could maintain its asymmetry. Near/far side asymmetric tidal heating could serve as a trigger for uneven lunar crustal growth.