Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p43e..01z&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #P43E-01
Physics
[6235] Planetary Sciences: Solar System Objects / Mercury
Scientific paper
The surface and interior of Mercury preserve collectively the record of processes that contributed to the planet's thermal evolution: accretion, differentiation, orbital, rotational and internal dynamics, impact cratering, tectonics and volcanism. Reconstructing Mercury's evolution requires relating internal structure and planetary dynamics to topography, chemistry and surface geology. Observations from the Mercury Laser Altimeter (MLA) and Radio Science (RS) experiments from the flyby and orbital phases of the MESSENGER mission are being analyzed in support of that goal. The MLA obtains returns from the surface at slant ranges <1500 km and has yielded a geodetically-referenced model of northern hemisphere topography. Elevations in the northern hemisphere exhibit a symmetric, unimodal distribution with short tails and a dynamic range of 9.6 km. A spherical harmonic fit of low-latitude topography confirms the ellipsoidal shape and orientation of the equator and a 0.015o downward to east slope indicative of an offset between the center of mass and center of figure in the equatorial plane. This distinctive feature of the planetary shape reflects an east-west hemispheric difference in internal structure that could potentially arise from crustal thickness or crustal density variations, large-scale mantle density variations, or topography along the Mercury's core-mantle boundary. The floor of the major impact basin Caloris has been significantly modified, with the northern sections rising above the basin rim. The north polar region shows an irregular topographic depression of 2-4 km depth centered on the north pole. The feature may have migrated to the pole due to reorientation of the planet's inertia axes. The depression could represent a non-hydrostatic contribution to the planetary flattening that must be isolated and removed prior to interpreting the flattening in the context of the radial distribution of interior mass. Analysis of X-band Doppler tracking of MESSENGER has resulted in a 20th degree and order global gravity field, with high degree and order coefficients resolved only in the north. Present are mass anomalies that correlate with some impact basins that hold the promise of modeling to ascertain regional crust and upper mantle structure.
Barnouin Olivier S.
Hauck Steven A.
Head James W.
Johnson Clifton L.
Lemoine Frank G.
No associations
LandOfFree
The Geophysics of Mercury: Shape, Interior Structure and Thermal Evolution from MESSENGER does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Geophysics of Mercury: Shape, Interior Structure and Thermal Evolution from MESSENGER, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Geophysics of Mercury: Shape, Interior Structure and Thermal Evolution from MESSENGER will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-872644