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Detection of the Chandler Wobble of Mars From Orbiting Spacecraft
Author(s) -
Konopliv Alex S.,
Park Ryan S.,
Rivoldini Attilio,
Baland RoseMarie,
Le Maistre Sebastien,
Van Hoolst Tim,
Yseboodt Marie,
Dehant Veronique
Publication year - 2020
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 - 10.1029/2020gl090568
Subject(s) - polar motion , mars exploration program , speed wobble , geology , geodesy , orbiter , nutation , martian , atmosphere of mars , geophysics , moment of inertia , physics , astrobiology , earth's rotation , astronomy , classical mechanics
For the first time for any planetary body other than the Earth, the free wobble of the pole called the Chandler wobble has been detected for Mars with a period of 206.9 ± 0.5 days and amplitude of 10 cm from radio tracking observations of Mars Odyssey, Mars Reconnaissance Orbiter (MRO), and Mars Global Surveyor (MGS), in order of decreasing sensitivity. The motion of the rotation pole location on the surface of Mars, or polar motion, is observed using two different approaches: (1) joint global estimates of Mars' orientation and its gravity field and (2) time series solutions of C 21 and S 21 . For Mars interior models, the Chandler wobble period is combined with other measurements including the moments of inertia from our estimated precession rate ψ ̇ = − 7603.9 ± 1.3 mas / year and tidal Love number k 2 = 0.169 ± 0.006. The Chandler wobble period constrains the rheology of the Martian mantle and in particular its long‐term frequency dependence.