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The Coriolis effect on mass wasting during the Rheasilvia impact on asteroid Vesta
Author(s) -
Otto K. A.,
Jaumann R.,
Krohn K.,
Spahn F.,
Raymond C. A.,
Russell C. T.
Publication year - 2016
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 - 10.1002/2016gl071539
Subject(s) - impact crater , mass wasting , asteroid , stage (stratigraphy) , mass distribution , curvature , geology , asteroid belt , mechanics , astrobiology , physics , geodesy , astrophysics , geometry , seismology , mathematics , paleontology , landslide , galaxy
We investigate the influence of the Coriolis force on mass motion related to the Rheasilvia impact on asteroid Vesta. Observations by the NASA Dawn mission revealed a pattern of curved radial ridges, which are related to Coriolis‐deflected mass‐wasting during the initial modification stage of the crater. Utilizing the projected curvature of the mass‐wasting trajectories, we developed a method that enabled investigation of the initial mass wasting of the Rheasilvia impact by observational means. We demonstrate that the Coriolis force can strongly affect the crater formation processes on rapidly rotating objects, and we derive the material's velocities (28.9 ± 22.5 m/s), viscosities (1.5–9.0 × 10 6 Pa s) and coefficients of friction (0.02–0.81) during the impact modification stage. The duration of the impact modification stage could be estimated to (1.1 ± 0.5) h. By analyzing the velocity distribution with respect to the topography, we deduce that the Rheasilvia impactor hit a heterogeneous target and that the initial crater walls were significantly steeper during the modification stage.