CERES, ONE YEAR BEFORE DAWN’S ARRIVAL

Ceres occupies a special place in the Solar system as a remnant protoplanet and witness of the early solar system dynamical evolution. The likely presence of free ice in this large body bears important implications on its evolution that may be similar to evolution scenarios proposed for some of the warmest icy satellites. Incidentally, Ceres is about the same size as Charon and Saturn’s satellite Dione, which leads to interesting comparative planetology research on internal evolution, and on the prospect for hydrothermal activity as a function of accretion environments and original volatile composition. Indeed multiple open questions revolving around increased knowledge of Ceres’ composition deal with origin and habitability and may be addressed with observations to be returned by the Dawn spacecraft in 2014-2015. In particular, constraints on early transfer of icy material across the Solar system predicted by the Nice model may be tested if fine chemistry measurements of Ceres’ surface can be achieved. This in turn would be key to understanding the origin of volatiles in the inner Solar system. Constraints on internal evolution may be inferred from surface composition as well. For example, Ceres displays carbonates, and possibly brucite, whose origin points to an early phase of hydrothermal activity. Should Dawn’s VIR and GRaND observations confirm this scenario, then the display of this high-temperature material on the surface would provide a strong evidence for a past phase of endogenic activity and resurfacing. At the time of this presentation, Dawn will be a merely year away from encountering Ceres!!

Acknowledgement: This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.