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A scheme for lunar inner core detection
Author(s) -
Williams James G.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028185
Subject(s) - inner core , equator , physics , ecliptic , geology , mantle (geology) , geodesy , geophysics , gravitational field , outer core , astronomy , latitude , magnetic field , quantum mechanics , solar wind
Very precise measurements of the lunar gravity field could detect a solid inner core. For synchronous rotation, the equator planes of the inner core and mantle should be tilted with respect to the ecliptic plane and precess along that plane with the same 18.6 yr period. Generally, two different tilts would cause a static inner core gravity field to appear as small periodic (27.212 d) variations in the mantle‐referenced C 21 and S 21 coefficients. Tidal variations also contribute to the C 21 variation so a much improved k 2 Love number would be required. Model computations suggest that the inner core signature is likely to be very small requiring sensitive gravity measurements. In principle, a signature analogous to the Moon's should be present for other synchronous satellites with interior liquid layers and also Mercury.