Ceres internal structure from geophysical constraints

Scott D. KING1, Julie C. CASTILLO-ROGEZ2, M. J. TOPLIS3, Michael T. BLAND4, Carol A. RAYMOND2, and Christopher T. RUSSELL5
Meteoritics & Planetary Science (in Press) Link to Article [DOI: 10.1111/maps.13063]
1Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061, USA
2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
3Institut de Recherche d’Astrophysique et Planetologie, University of Toulouse, Toulouse, France
4US Geological Survey, Astrogeology Science Center, Flagstaff, Arizona 86001, USA
5Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095, USA
Published by arrangement with John Wiley & Sons

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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