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Further constraints on the deep lunar interior
Author(s) -
Khan A.,
Mosegaard K.
Publication year - 2005
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 - 10.1029/2005gl023985
Subject(s) - geology , mantle (geology) , geophysics , moment of inertia , shear (geology) , dissipation , shear velocity , groenlandia , inner core , geodesy , physics , mechanics , petrology , geomorphology , ice sheet , turbulence , quantum mechanics , thermodynamics
We have inverted the most recent set of geophysical observations pertinent to lunar interior properties, including mass M and moment of inertia I as determined by Lunar Prospector, the two Love numbers k 2 and h 2 as well as monthly tidal dissipation Q obtained from more than 35 years of lunar laser ranging data. In wanting to assess the ability of these parameters to constrain lunar mantle and core structure, we have used a stochastically based sampling algorithm to invert the geophysical data to obtain radial density and shear wave velocity profiles. The results indicate a small liquid Fe core ( r < 400 km), with a shear wave velocity close to 0 km/s and a density of around 7 g/cm 3 . This is further corroborated by calculating the Bayes factor for the hypothesis that the lunar core is fluid against the hypothesis that it is solid, which is >1, thereby favouring the fluid core hypothesis. In addition, shear wave velocities for the lower mantle region (depths > 1100 km) are generally found to be lower than upper mantle velocities and can be interpreted as implying the presence of partial melt, which can explain the unusually low lunar monthly tidal Q of ∼30.