Book contents
- Vesta and Ceres: Insights from the Dawn Mission for the Origin of the Solar System
- Cambridge Planetary Science
- Vesta and Ceres
- Copyright page
- Contents
- Contributors
- Preface
- Part I Remote Observations and Exploration of Main Belt Asteroids
- Part II Key Results from Dawn’s Exploration of Vesta and Ceres
- 3 Protoplanet Vesta and HED Meteorites
- 4 The Internal Evolution of Vesta
- 5 Geomorphology of Vesta
- 6 The Surface Composition of Vesta
- 7 Ceres’ Surface Composition
- 8 Carbon and Organic Matter on Ceres
- 9 Ammonia on Ceres
- 10 Geomorphology of Ceres
- 11 Ceres’ Internal Evolution
- 12 Geophysics of Vesta and Ceres
- Part III Implications for the Formation and Evolution of the Solar System
- Index
- Plate Section (PDF Only)
- References
12 - Geophysics of Vesta and Ceres
from Part II - Key Results from Dawn’s Exploration of Vesta and Ceres
Published online by Cambridge University Press: 01 April 2022
- Vesta and Ceres: Insights from the Dawn Mission for the Origin of the Solar System
- Cambridge Planetary Science
- Vesta and Ceres
- Copyright page
- Contents
- Contributors
- Preface
- Part I Remote Observations and Exploration of Main Belt Asteroids
- Part II Key Results from Dawn’s Exploration of Vesta and Ceres
- 3 Protoplanet Vesta and HED Meteorites
- 4 The Internal Evolution of Vesta
- 5 Geomorphology of Vesta
- 6 The Surface Composition of Vesta
- 7 Ceres’ Surface Composition
- 8 Carbon and Organic Matter on Ceres
- 9 Ammonia on Ceres
- 10 Geomorphology of Ceres
- 11 Ceres’ Internal Evolution
- 12 Geophysics of Vesta and Ceres
- Part III Implications for the Formation and Evolution of the Solar System
- Index
- Plate Section (PDF Only)
- References
Summary
Geophysical data from Dawn’s mission revealed complex and divergent internal structure evolutionary paths for Vesta and Ceres. Dawn’s data indicated that Vesta has a differentiated internal structure with uncompensated topography and Ceres is partially differentiated with compensated topography. Vesta experienced a magma ocean state, leading to effective early shape relaxation. Vesta’s current non-hydrostatic shape is dominated by Rheasilvia and Veneneia impact basins, formed when Vesta was too rigid to relax. However, northern terrains still reflect its pre-impact, closer-to-hydrostatic shape. Ceres incorporated abundant volatile material upon its accretion and subsequently underwent ice–rock fractionation. Observed surface aqueous alteration indicates extensive past hydrothermal circulation that facilitated efficient heat transfer and preserved Ceres’ interior in a relatively cool state. Lower viscosities at depth allowed isostatic compensation of Ceres’ long-wavelength topography. The high inferred abundance of water ice, hydrated salts, and/or clathrate phases suggest previous globally significant regions of solute-rich fluids that froze from the surface inward, leading to the vertical density gradient inferred from Dawn’s Second Extended Mission (XM2) high-resolution gravity data. This, coupled with thermal modeling, indicated that Ceres could have brine reservoirs, at least regionally, which were likely mobilized by the Occator crater-forming impact, leading to long-lived brine extrusion and faculae formation.
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- Vesta and CeresInsights from the Dawn Mission for the Origin of the Solar System, pp. 173 - 196Publisher: Cambridge University PressPrint publication year: 2022