Lunar interior properties from frequency-dependent Love numbers and dissipation newly determined from GRAIL and LRO data
Sander Goossens
We have analyzed Gravity Recovery and Interior Laboratory (GRAIL) and Lunar Reconnaissance Orbiter (LRO) tracking data to determine the Moon's frequency-dependent tidal response, expressed by monthly and yearly values for the potential degree 2 Love number k2 and dissipation quality factor Q. Williams and Boggs (2015) provide series expressions for terms of different periods for the tidal and dissipation gravitational effects. We have estimated scale factors for these effects and are thus able to derive values for the monthly and yearly k2 and Q. We refer to our paper for the details. The values we derived are given in Table 1, together with those from Williams and Boggs (2015).
| Tidal term | Williams and Boggs (2015) | This work |
| Monthly k2 | 0.02416 ± 0.00022 | 0.024053 ± 0.00022 |
| Yearly k2 | - | 0.025909 ± 0.00070 |
| Monthly Q | 38 ± 4 | 36.73 ± 3.519 |
| Yearly Q | 41 ± 9 | 53.09 ± 13.53 |
We have used these values in a Markov Chain Monte Carlo analysis to determine the Moon's interior properties, with a special focus on the existence of a low-viscosity zone (LVZ) at the bottom of the mantle, which is strongly suggestive of partial melting. Our analysis used the new monthly and yearly constraints, and we considered different rheological laws (Maxwell, Andrade, Sundberg-Cooper) for the mantle's response. Here, we present the results of our MCMC analysis. We analyzed structures with and without an LVZ for each rheological law.
Data
MCMC results for the Maxwell model with an LVZ (ZIP, 99 MB)
MCMC results for the Maxwell model without an LVZ (ZIP, 4 MB)
MCMC results for the Andrade model with an LVZ (ZIP, 76 MB)
MCMC results for the Andrade model without an LVZ (ZIP, 15 MB)
MCMC results for the Sundberg-Cooper model with an LVZ (ZIP, 101 MB)
MCMC results for the Sundberg-Cooper model without an LVZ (ZIP, 45 MB)
See '.txt' files inside the ZIP archives for details on the format of the included '.dat' model output files.
Data Usage Policy
Please cite the following reference when using any of the products described above:
Paper: Goossens et al., A low-viscosity lower lunar mantle implied by measured monthly and yearly tides, AGU Advances, accepted, 2024, doi:10.1029/2024AV001285.
Dataset: Goossens, S. (2024). Lunar interior models from frequency-dependent Love numbers and dissipation determined from GRAIL and LRO data [Data set]. NASA Goddard Space Flight Center Planetary Geodesy Data Archive. doi:10.60903/gsfcpgda-graillro-interiormodels.
Funding
This project was supported by the Lunar Data Analysis Program.
References
Williams, J. G., and D. H. Boggs (2015), Tides on the Moon: Theory and determination of dissipation, J. Geophys. Res. Planets, 120, 689–724, doi:10.1002/2014JE004755.