Ceres internal structure from geophysical constraints |
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| Authors: | Scott D King Julie C Castillo‐Rogez M J Toplis Michael T Bland Carol A Raymond Christopher T Russell |
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| Institution: | 1. Department of Geosciences, Virginia Tech, Blacksburg, Virginia, USA;2. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA;3. Institut de Recherche d'Astrophysique et Planétologie, University of Toulouse, Toulouse, France;4. US Geological Survey, Astrogeology Science Center, Flagstaff, Arizona, USA;5. Earth, Planetary, and Space Sciences, University of California, Los Angeles, California, USA |
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| Abstract: | Thermal evolution modeling has yielded a variety of interior structures for Ceres, ranging from a modestly differentiated interior to more advanced evolution with a dry silicate core, a hydrated silicate mantle, and a volatile‐rich crust. Here we compute the mass and hydrostatic flattening from more than one hundred billion three‐layer density models for Ceres and describe the characteristics of the population of density structures that are consistent with the Dawn observations. We show that the mass and hydrostatic flattening constraints from Ceres indicate the presence of a high‐density core with greater than a 1σ probability, but provide little constraint on the density, allowing for core compositions that range from hydrous and/or anhydrous silicates to a mixture of metal and silicates. The crustal densities are consistent with surface observations of salts, water ice, carbonates, and ammoniated clays, which indicate hydrothermal alteration, partial fractionation, and the possible settling of heavy sulfide and metallic particles, which provide a potential process for increasing mass with depth. |
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