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Reorientation of Vesta: Gravity and tectonic predictions
Author(s) -
Matsuyama I.,
Nimmo F.
Publication year - 2011
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 - 10.1029/2011gl047967
Subject(s) - geology , structural basin , southern hemisphere , tectonics , isotropy , orientation (vector space) , geodesy , geophysics , seismology , physics , geometry , paleontology , climatology , optics , mathematics
Vesta's large southern hemisphere impact basin is likely to have caused reorientation. However, because the basin is not centred at the south pole, Vesta likely also has a remnant rotational figure. Reorientation of ≈6° is predicted to have occurred based on the dimensions of the basin. Existing measurements of Vesta's shape are consistent with ≈20° or less reorientation, and ≈20% or less despinning. Both the remnant rotational figure and the basin contribute to the degree‐2 gravity coefficients, which will be measured by the Dawn mission and will provide a test of the reorientation hypothesis. Reorientation and despinning also give rise to stresses. Vesta's stress state is likely to be dominated by isotropic contraction due to cooling (which does not affect the gravity coefficients). However, the orientation of the resulting thrust features will be controlled by the amount of reorientation and despinning, providing another observational test.