| Session Details | |
| Section | PS - Planetary Sciences |
| Session Title | Dwarf Planet Ceres After Dawn |
| Main Convener | Dr. Jennifer Scully (Jet Propulsion Laboratory, California Institute of Technology, United States) |
| Co-convener(s) | Dr. Jian-Yang Li (Planetary Science Institute, United States) Dr. Norbert Schorghofer (Planetary Science Institute, United States) Dr. Wing-Huen Ip (National Central University, Taiwan) |
| Session Description | Since 2015, the Dawn spacecraft has orbited Ceres, the largest body in the asteroid belt (mean radius of ~470 km), and has returned a wealth of data. Now that Dawn is in the latter stages of its mission, this session aims to summarize and synthesize our current understanding of Ceres, and welcomes submissions that study Ceres through a variety of techniques, including Dawn and telescopic data analyses, modeling studies, analog studies and laboratory investigations. This session covers geophysical, geomorphological, geochemical, and atmospheric aspects of Ceres, and also invites contributions that place Ceres in the context of astrobiology or water delivery to Earth. The results of the Dawn mission show that Ceres is an intriguing body that has undergone a diverse suite of geologic, geochemical and geophysical processes. Ceres is weakly differentiated into a rocky and comparatively dense interior and a more volatile-rich outer layer. There is on average ~30-40% water ice in the outermost layer. Water ice facilitates the formation of particular types of lobate flows and is likely located in some polar permanently shadowed craters. Sputtering of near-surface water ice by solar energetic particle events may form a weak transient atmosphere. Phyllosilicates are homogeneously distributed across the surface, indicating global scale alteration, possibly in an ancient ocean. Organic materials have also been detected on the surface. There are numerous impact craters, which are associated with various forms of mass wasting, impact melt and pitted terrain (formed by the loss of impact-heated volatiles). There is evidence for large and small scale fracturing. Occator crater contains distinctly bright regions, called faculae, which are proposed to be the solid residues of brines sourced in the subsurface. Ahuna Mons is a ~4 km high edifice interpreted as a recently formed viscous cryovolcanic dome. |