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| Titel |
A new lunar gravity field model from SELENE and historical satellite tracking data |
| VerfasserIn |
K. Matsumoto, S. Goossens, N. Namiki, Y. Ishihara, Q. Liu, F. Kikuchi, T. Iwata, H. Noda, H. Hanada |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022456
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| Zusammenfassung |
| The SELENE (Kaguya) mission has successfully completed its nominal mission phase at the
end of October 2008. The tracking data of the three satellites of Main, Rstar, and Vstar have
also been accumulated and are to be still increased during its extended mission phase. This
presentation reports the current status of lunar gravity field estimation including the
acquisition status of the tracking data and the latest gravity field model estimated from the
Kaguya and the historical satellite tracking data. Classification and compensation
mechanism of impact basins are discussed based on the gravity and topography
data.
One year of Kaguya tracking data (from 20 October, 2007, until 30 October, 2008) have
been combined with pre-Kaguya tracking data to create a spherical harmonics model of
degree and order 100, named SGM100g (SELENE Gravity Model). The new model
successfully reveals the ring-shaped free-air gravity anomalies in the far-side which
correspond well to the topographic features of impact basins. There are still some 4-way
Doppler data gaps in the far-side northern hemisphere, but some of them will be filled by the
end of Rstar’s lifetime (around 12 Feb. 2009). The large gravity error in the far-side which
existed in pre-SELENE model such as LP100K is drastically reduced and asymmetric error
distribution between the near-side and the far-side is mitigated. Mainly thanks to the 4-way
Doppler measurements the gravity coefficients below degree and order 55 are now
determined by observations with more than 90% of contribution factor. Although
differential VLBI data between Rstar and Vstar are not yet included in SGM100g, we
will present a preliminary result of including about 4 months of same-beam VLBI
data.
Solutions for the polar moment of inertia C∕MR2 and the lunar degree 2 Love number k2
for SGM100g are 0.3934 |
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