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Mercury's core - The effect of obliquity on the spin-orbit constraintsConstraints were previously placed on various properties of a Mercurian liquid core for compatibility with Mercury's escape from the stable spin-orbit resonance with the spin angular velocity equal to twice the orbital mean motion (the 2n resonance), under the assumption that the planet's obliquity was nearly zero at the time of resonance passage. Capture probabilities at arbitrary nonzero obliquities for the 2n resonance are determined for the cases where the core is strongly or weakly coupled to the mantle. It is found that the capture probabilities are reduced to below unity for all core-fluid viscosities in the weak-coupling limit, but are almost unchanged in the strong-coupling limit. The reduction in capture probability is attributed to reduction of the mantle's spin angular velocity by the core-mantle interaction, which would also reduce the obliquity to negligibly small values before the 2n resonance was even reached. It is concluded that the constraints on the core may still be maintained since Mercury most likely passed through the 2n resonance with nearly zero obliquity.
Document ID
19770063419
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Peale, S. J.
(California Univ. Santa Barbara, CA, United States)
Boss, A. P.
(California, University Santa Barbara, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
August 10, 1977
Publication Information
Publication: Journal of Geophysical Research
Volume: 82
Subject Category
Lunar And Planetary Exploration
Accession Number
77A46271
Funding Number(s)
CONTRACT_GRANT: NGR-05-010-062
Distribution Limits
Public
Copyright
Other

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