000008189 001__ 8189
000008189 005__ 20260928151412.0
000008189 0247_ $$2DOI$$a10.5194/angeo-44-287-2026
000008189 037__ $$aSCART-2026-0156
000008189 100__ $$aFolgueira, M.
000008189 245__ $$aEffect of a non-hydrostatic core-mantle boundary on the nutations and Length-of-day of Mars
000008189 260__ $$c2026
000008189 520__ $$aDynamic loads in planetary mantles have the potential to deform the core-mantle boundary (CMB). On Earth, subducting slabs primarily induce a degree 2–order 2 deformation of the CMB in the spherical harmonic (SH) ref- erence system. On Mars, the presence of the dichotomy and of the Tharsis region could produce loading across multiple degrees and orders, including degree-1, degree 2–order 2, de- gree 2–order 0, and degree 3–order 3 components. Thanks to the InSight (Interior exploration using Seismic Investiga- tions, Geodesy, and Heat Transport) mission’s radio science experiment, observations of Mars’ nutations are now avail- able. Periodic length-of-day (LOD) variations of Mars have been detected first by radio tracking the Viking landers, and InSight data have indicated the presence of a secular trend in LOD. In the case of nutations, the Martian core’s non- hydrostatic flattening plays a first-order role in determining nutation amplitudes. In this study, we explore second-order effects arising from dynamic topography at the CMB. We compute the pressure exerted on the CMB topography in- side Mars’ liquid core and evaluate the resulting topographic pressure torque acting on the boundary, which can influence both nutations and LOD variations. Our results show that, albeit at microarcsecond (µarcsec) level – well below cur- rent observational thresholds, the most significant contribu- tion to nutations arises from degree 2–order 2 component. As for LOD variations, while Earth exhibits notable contri- butions from inertial wave resonances, the situation on Mars is different. The planet’s tidal LOD variations have periods that are either too long or too far apart from those of inertial waves. Consequently, the associated contributions fall below the level of detectability.
000008189 536__ $$aPRODEX PlanetInterior/$$cPRODEX PlanetInterior/$$fPRODEX PlanetInterior
000008189 594__ $$aNO
000008189 700__ $$aDehant, V.
000008189 700__ $$aPuica, M.
000008189 700__ $$aVan Hoolst, T.
000008189 773__ $$c287-301$$pAnnales Geophysicae$$v44$$y2026
000008189 8560_ $$ftim.vanhoolst@ksb-orb.be
000008189 8564_ $$s1924396$$uhttps://publi2-as.oma.be/record/8189/files/Folgueira_AnnGeo_2026.pdf
000008189 8564_ $$s3484$$uhttps://publi2-as.oma.be/record/8189/files/Folgueira_AnnGeo_2026.gif?subformat=icon$$xicon
000008189 8564_ $$s3840$$uhttps://publi2-as.oma.be/record/8189/files/Folgueira_AnnGeo_2026.jpg?subformat=icon-180$$xicon-180
000008189 905__ $$apublished in
000008189 980__ $$aREFERD