Thanks to NASA's Dawn mission, the last half-decade has witnessed a significant advance in our understanding of Ceres. The largest object between the orbits of Mars and Jupiter, Ceres is the most water-rich body in the inner solar system after Earth which shows evidence of brine-driven activity in its recent history, and even possibly at the present. The potential existence of a subsurface ocean or regional seas in Ceres and its salt- and organic-rich composition underscore its astro-biological significance. After signaling the discovery of the asteroid belt more than two centuries ago, Ceres once again reveals new insights for us to understand the formation, evolution, and habitability of this large icy body in our solar system. This book reviews the current state of knowledge about Ceres after the extensive scientific exploration by the Dawn mission. Starting from the introduction of the discovery of Ceres and what we know about this enigmatic world before Dawn's arrival, each chapter focuses on one aspect of Ceres, including its surface composition, its geology, the role of water ice in shaping Ceres's surface, its interior structure, and expressions of cryovolcanic or brine activity at the surface. Following this framework, the book addresses the astro-biological significance of Ceres. The last chapter summarizes the new questions opened by the Dawn mission and the next step to exploring the dwarf planet closest to Earth.
Author(s): Jian-Yang Li, Julie C. Castillo-Rogez
Series: Advances In Planetary Science, 6
Publisher: World Scientific Publishing
Year: 2022
Language: English
Pages: 254
City: Singapore
Contents
Preface
About the Authors
Chapter 1 Discovery of Ceres and the Asteroid Belt
1.1 Discovery of Ceres
1.2 Discovery of the Asteroid Belt
References
Chapter 2 Pre-Dawn Exploration
2.1 Overview
2.2 Bulk Properties
2.2.1 Early Photometry
2.2.2 Size and Shape
2.2.3 Surface Features
2.2.4 Thermal Properties
2.2.5 Mass
2.3 Surface Composition and Taxonomy
2.3.1 Visible and Near-Infrared (0.4–2.5 μm)
2.3.2 Ultraviolet (UV) (<0.4 μm)
2.3.3 3 μm Region (2.5–5 μm)
2.3.4 Mid-Infrared (5–13 μm)
2.4 Internal Evolution Modeling
2.5 Volatiles
2.6 Summary: State of Knowledge and Open Questions Prior to Dawn’s Arrival
References
Chapter 3 Dawn Mission Overview
3.1 Scientific Goals and Measurement Objectives
3.2 Spacecraft and Payloads
3.2.1 Dawn Spacecraft
3.2.2 Framing Camera
3.2.3 VIR Spectrometer
3.2.4 Gamma Ray and Neutron Detector
3.2.5 Radio Science
3.3 Science Operations
3.4 Summary of Key Results
References
Chapter 4 Surface Composition
4.1 Phyllosilicates
4.2 Carbonates
4.3 Organics
4.3.1 Ernutet Crater
4.3.2 Regolith
4.4 Surface Water Ice
4.5 Iron and Potassium
4.6 Interpretation of Ceres’s Surface Composition
References
Chapter 5 Geology
5.1 Global Geology
5.2 General Crater Properties
5.3 Surface Ages from Crater Counting
5.4 Tectonics
References
Chapter 6 Water Ice
6.1 Exposed Surface Water Ice
6.2 Ice-Related Morphological Features
6.2.1 Crater Morphology
6.2.2 Lobate Landslides and Ejecta
6.2.3 Domes and Mounds
6.2.4 Pits, Depressions, and Scarps
6.2.5 Fractures, Grooves, Channels, and Troughs
6.3 Exosphere
6.3.1 Exosphere Detection by Dawn
6.3.2 Ground-Based Observations
6.3.3 Source of Water Outgassing
6.4 Implications on Ceres Cryosphere
References
Chapter 7 Interior Structure
7.1 Gravity
7.2 Inferences from Admittance
7.3 Constraints from Geological Observations
7.4 Current Understanding of Ceres’s Interior
7.5 Evolution of a Differentiated Ceres
7.5.1 Early Evolution
7.5.2 Long-Term Evolution
References
Chapter 8 Recent Activity
8.1 Ahuna Mons and Other Large Domes
8.2 Occator Crater
8.3 Origin of Bright Deposits Across Ceres
References
Chapter 9 Astrobiological Significance
9.1 Ceres’s Past Habitability Potential
9.2 Ceres’s Current Habitability Potential
9.3 Ceres’s Habitability Through Time
9.4 Relationships to Other Bodies
References
Chapter 10 Open Questions and Future Exploration
10.1 Open Questions at the End of the Dawn Mission
10.1.1 Origin of Ceres
10.1.2 Origin and Formation of Regolith
10.1.3 Interior Structure
10.1.3.1 Extent of Differentiation
10.1.3.2 Distribution (extent, geometry), and the Nature of Liquid
10.1.3.3 Crustal Evolution
10.1.4 Origin of Organic Matter
10.1.5 Origin of Exosphere
10.1.6 Drivers of Long-Term Geology Activity
10.1.7 Characterization of Habitability
10.2 Future Exploration of Ceres on Earth
10.2.1 Theoretical Modeling
10.2.2 Laboratory Studies
10.2.3 Earth-Based Observations
10.2.4 Terrestrial Analogs
10.3 Roadmap to the Future Exploration of Ceres
10.3.1 Possible Sites for Landed and Sample Return Missions
10.3.2 Possible Mission Architectures
References
Index
