Precession of the lunar core
Name
Wisdom article.pdf
Size
127.03 KB
Format
Adobe PDF
Checksum (MD5)
858e5411cbcb73e2e1f03dd1b48100ea
Author(s)
Meyer, Jennifer Ann
Wisdom, Jack
Date Issued
September 2010
Journal
Icarus
Publisher
Elsevier
Citation
Meyer, Jennifer, and Jack Wisdom. “Precession of the Lunar Core.” Icarus 211, no. 1 (January 2011): 921–924.
Version
Author's final manuscript
Abstract
Goldreich (Goldreich, P. [1967]. J. Geophys. Res. 72, 3135) showed that a lunar core of low viscosity would not precess with the mantle. We show that this is also the case for much of lunar history. But when the Moon was close to the Earth, the Moon’s core was forced to follow closely the precessing mantle, in that the rotation axis of the core remained nearly aligned with the symmetry axis of the mantle. The transition from locked to unlocked core precession occurred between 26.0 and 29.0 Earth radii, thus it is likely that the lunar core did not follow the mantle during the Cassini transition. Dwyer and Stevenson (Dwyer, C.A., Stevenson, D.J. [2005]. An Early Nutation-Driven Lunar Dynamo. AGU Fall Meeting Abstracts GP42A-06) suggested that the lunar dynamo needs mechanical stirring to power it. The stirring is caused by the lack of locked precession of the lunar core. So, we do not expect a lunar dynamo powered by mechanical stirring when the Moon was closer to the Earth than 26.0–29.0 Earth radii. A lunar dynamo powered by mechanical stirring might have been strongest near the Cassini transition.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.icarus.2010.09.016
