GRAIL, LLR, and LOLA constraints on the interior structure of the Moon

• Published in: Geophysical research letters 2016-08, Vol.43 (16), p.8365-8375
• Main Authors: Matsuyama, Isamu, Nimmo, Francis, Keane, James T., Chan, Ngai H., Taylor, G. Jeffrey, Wieczorek, Mark A., Kiefer, Walter S., Williams, James G.
• Format: Article
• Language: English
• Subjects: Constraints; Earth Sciences; Geophysics; Liquids; Love number; lunar interior; Mantle; Moments of inertia; Moon; Planetology; Rigidity; Sciences of the Universe; Transition layers
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL069952

The interior structure of the Moon is constrained by its mass, moment of inertia, and k2 and h2 tidal Love numbers. We infer the likely radius, density, and (elastic limit) rigidity of all interior layers by solving the inverse problem using these observational constraints assuming spherical symmetry. Our results do not favor the presence of a low rigidity transition layer between a liquid outer core and mantle. If a transition layer exists, its rigidity is constrained to 43−9+26 GPa, with a preference for the high rigidity values. Therefore, if a transition layer exists, it is more likely to have a rigidity similar to that of the mantle (∼70 GPa). The total (solid and liquid) core mass fraction relative to the lunar mass is constrained to 0.0098−0.0094+0.0066 and 0.0198−0.0049+0.0026 for interior structures with and without a transition layer, respectively, narrowing the range of possible giant impact formation scenarios. Key Points The interior structure of the Moon is constrained using the observed mass, moment of inertia, and Love numbers The probability distributions of the interior structure parameters are provided The presence of a low rigidity transition layer at the base of the mantle is not required