Dougherty / Esposito / Krimigis Saturn from Cassini-Huygens

1. Auflage 2009
ISBN: 978-1-4020-9217-6
Verlag: Springer-Verlag
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 805 Seiten

This book is one of two volumes meant to capture, to the extent practical, the scienti?c legacy of the Cassini-Huygens prime mission, a landmark in the history of planetary exploration. As the most ambitious and interdisciplinary planetary exploration mission ?own to date, it has extended our knowledge of the Saturn system to levels of detail at least an order of magnitude beyond that gained from all previous missions to Saturn. Nestled in the brilliant light of the new and deep understanding of the Saturn planetary system is the shiny nugget that is the spectacularly successful collaboration of individuals, - ganizations and governments in the achievement of Cassini-Huygens. In some ways the pa- nershipsformedandlessonslearnedmaybethemost enduringlegacyofCassini-Huygens.The broad, international coalition that is Cassini-Huygens is now conducting the Cassini Equinox Mission and planning the Cassini Solstice Mission, and in a major expansion of those fruitful efforts, has extended the collaboration to the study of new ?agship missions to both Jupiter and Saturn. Such ventures have and will continue to enrich us all, and evoke a very optimistic vision of the future of international collaboration in planetary exploration. The two volumes in the series Saturn from Cassini-Huygens and Titan from Cassini- Huygens are the direct products of the efforts of over 200 authors and co-authors. Though each book has a different set of three editors, the group of six editors for the two volumes has worked together through every step of the process to ensure that these two volumes are a set.

Michele Dougherty, Cassini Saturn Orbiter (NASA/ESA) - Acting Principal Investigator (PI) for magnetometer instrument.   Dr. Esposito the principal investigator of the Ultraviolet Imaging Spectrograph (UVIS) experiment on the Cassini space mission to Saturn. He was chair of the Voyager Rings Working Group. As a member of the Pioneer Saturn imaging team, he discovered Saturn's F ring. He has been a participant in numerous US, Russian and European space missions and used the Hubble Space Telescope for its first observations of the planet Venus. He was awarded the Harold C. Urey Prize from the American Astronomical Society, The NASA Medal for Exceptional Scientific Achievement, and the Richtmyer Lecture Award from the American Association of Physics Teachers and the American Physical Society. Dr. Esposito has written his Ph.D dissertation, numerous scientific publications, scholarly reviews on the topic of planetary rings as well as the Cambridge University Press book Planetary Rings. Along with his students and colleagues he continues to actively research the nature and history of planetary rings at the University of Colorado, where he has been since 1977. He is now Professor of Astrophysical and Planetary Sciences and a member of the Laboratory for Atmospheric and Space Physics (LASP). He has been an officer of the Division for Planetary Sciences of the American Astronomical Society and of the Committee for Space Research (COSPAR) of the International Council of Scientific Unions. He was chair of the National Academy of Sciences Committee on Planetary and Lunar Exploration (COMPLEX). He is a member of American Astronomical Society, American Geophysical Union and International Astronomical Union. Dr. Stamatios (Tom) Krimigis has been at APL since 1968, after earning his B. Physics from the University of Minnesota (1961), and his M.S. (1963) and Ph.D. (1965) in Physics from the University of Iowa and serving as Assistant Professor of Physics and Astronomy there. He became Supervisor of Space Physics and Instrumentation in the Space Department, Chief Scientist in 1980, Department Head in 1991, and Emeritus Head in 2004. He is Principal Investigator on several NASA spacecraft, including Voyagers 1 and 2 to the Outer Planets and the Voyager Interstellar Mission, and the Cassini mission to Saturn and Titan. He has designed and built instruments that have flown to seven of the nine planets, and hopes to complete the set with his participation in the MESSENGER mission to Mercury and New Horizons mission to Pluto. He has published more than 370 papers in journals and books on the physics of the sun, interplanetary medium, planetary magnetospheres, and the heliosphere. He is recipient of NASA's Exceptional Scientific Achievement Medal twice, is a Fellow of the American Physical Society, American Geophysical Union, and American Association for the Advancement of Science, recipient of COSPAR's Space Science Award in 2002, a recipient of the Basic Sciences Award of the International Academy of Astronautics where he serves on the Board of Trustees, and was elected recently to the newly established chair of 'Science of Space' of the Academy of Athens.

Autoren/Hrsg.

Dougherty, Michele

Esposito, Larry

Krimigis, Stamatios

Inhaltsverzeichnis

1;Preface;5
2;Contents;6
3;Chapter 1 Overview;8
3.1;1.1 Introduction;8
3.2;1.2 Organization of This Volume;8
3.3;1.3 Synopsis of theMain Results for the Saturn System;8
3.3.1;1.3.1 Origin and Interior;9
3.3.2;1.3.2 Saturn’s Atmosphere;9
3.3.3;1.3.3 Magnetosphere;10
3.3.4;1.3.4 Saturn’s Rings;10
3.3.5;1.3.5 Icy Satellites;11
3.4;1.4 Open Questions and FutureWork;12
3.4.1;1.4.1 Origin and Interior;12
3.4.2;1.4.2 Saturn’s Atmosphere;12
3.4.3;1.4.3 Saturn’s Magnetosphere;13
3.4.4;1.4.4 Saturn’s Rings;13
3.4.5;1.4.5 The Satellite System;14
3.5;1.5 Continued Saturn System Exploration;15
3.6;References;15
4;Chapter 2 Review of Knowledge Prior to the Cassini-Huygens Mission and Concurrent Research;16
4.1;2.1 Introduction;16
4.2;2.2 Saturn’s Composition;17
4.2.1;2.2.1 Brief Historical Overview;17
4.2.2;2.2.2 Bulk Composition: H2, He/CH4;17
4.2.3;2.2.3 Tropospheric Composition;18
4.2.3.1;2.2.3.1 Ammonia,Water, and Hydrogen Sulfide;18
4.2.4;2.2.4 Stratospheric Composition;21
4.2.4.1;2.2.4.1 Hydrocarbons and Photochemistry;21
4.2.4.2;2.2.4.2 External Supply of Oxygen;22
4.2.4.3;2.2.4.3 Isotopic Ratios;22
4.3;2.3 Saturn’s Interior;23
4.4;2.4 Saturn’s Clouds and Aerosols;23
4.4.1;2.4.1 Pioneer/Voyager Era Measurements of Aerosol Structure;23
4.4.2;2.4.2 From Pioneer/Voyager to Cassini: Earth-Based Observations of Aerosol Structure;24
4.5;2.5 Saturn’s Temperatures;26
4.6;2.6 Saturn’s Atmospheric Dynamics;30
4.7;2.7 Saturn’s Upper Atmosphere and Auroral Emission;33
4.7.1;2.7.1 Ultraviolet Auroral Observations;33
4.7.2;2.7.2 Infrared Auroral Observations;34
4.8;2.8 Planetary Magnetic Field andMagnetosphere;36
4.8.1;2.8.1 Magnetic Field;36
4.8.2;2.8.2 Magnetospheric Plasma Environment;38
4.8.3;2.8.3 Energetic Particles;39
4.8.4;2.8.4 PlasmaWaves;42
4.8.5;2.8.5 Summary of Magnetosphere;43
4.9;2.9 Saturn’s Ring System;43
4.9.1;2.9.1 Particle Size Distribution;45
4.9.2;2.9.2 Ring Particle Composition;46
4.9.3;2.9.3 Origin and Evolution;47
4.10;2.10 Icy Satellites;48
4.10.1;2.10.1 Introduction;48
4.10.2;2.10.2 Sources of Information;48
4.10.2.1;2.10.2.1 Dimensions, Densities, and Rotational Properties;48
4.10.2.2;2.10.2.2 Surface Compositions and Surface Optical Properties;48
4.10.2.3;2.10.2.3 Geology;49
4.10.3;2.10.3 The Eight Large, Airless Satellites;49
4.10.3.1;2.10.3.1 Mimas;49
4.10.3.2;2.10.3.2 Enceladus;49
4.10.3.3;2.10.3.3 Tethys;50
4.10.3.4;2.10.3.4 Dione;51
4.10.3.5;2.10.3.5 Rhea;51
4.10.3.6;2.10.3.6 Hyperion;51
4.10.3.7;2.10.3.7 Iapetus;52
4.10.3.8;2.10.3.8 Phoebe;52
4.10.4;2.10.4 The Small Satellites;52
4.10.4.1;2.10.4.1 Satellites Near the Rings and Associated with Larger Satellites;52
4.10.4.2;2.10.4.2 Irregular Satellites;52
4.11;References;53
5;Chapter 3 Origin of the Saturn System;62
5.1;3.1 Introduction;62
5.2;3.2 Planet and Satellite Formation;63
5.2.1;3.2.1 Big Bang to the Solar Nebula;63
5.2.2;3.2.2 The Solar Nebula to Planets;63
5.2.2.1;3.2.2.1 The Inner Solar System;63
5.2.2.2;3.2.2.2 The Outer Solar System;63
5.2.2.3;3.2.2.3 Giant Planet Formation;64
5.2.2.4;3.2.2.4 Planetary Migration and the NiceModel;64
5.2.3;3.2.3 Circumplanetary Disks to Satellites;66
5.2.3.1;3.2.3.1 Formation of the Subnebula;67
5.2.3.2;3.2.3.2 Conditions for Satellite Accretion;67
5.3;3.3 Cassini Results and Discussion;69
5.3.1;3.3.1 Saturn and Rings;69
5.3.2;3.3.2 Satellite Composition;69
5.3.2.1;3.3.2.1 Satellite Bulk Densities;69
5.3.2.2;3.3.2.2 EquilibriumCondensation and Solar Composition;71
5.3.3;3.3.3 Satellite Structures;75
5.3.3.1;3.3.3.1 Background;75
5.3.3.2;3.3.3.2 Observations;75
5.3.4;3.3.4 Satellite Geological History;77
5.3.4.1;3.3.4.1 Crater ages;77
5.3.4.2;3.3.4.2 Iapetus’ Formation Time;77
5.4;References;78
6;Chapter 4 The Interior of Saturn;82
6.1;4.1 Diagnostics of Interior Structure and Dynamics;82
6.1.1;4.1.1 Gravity Field and Shape;82
6.1.2;4.1.2 Differential Rotation and Equations of State;83
6.2;4.2 Evolution of Saturn;85
6.3;4.3 Coupling of Detailed Evolutionary Models for Saturn to the Helium Partitioning Problem, and Comparison with Jupiter;86
6.4;4.4 Summary;87
6.5;References;87
7;Chapter 5 Saturn: Composition and Chemistry;89
7.1;5.1 Introduction;89
7.2;5.2 Observed Composition;90
7.2.1;5.2.1 Major Gases or Bulk Composition;90
7.2.1.1;5.2.1.1 Helium Abundance;90
7.2.1.2;5.2.1.2 The Para Fraction of Molecular Hydrogen;92
7.2.1.3;5.2.1.3 Carbon Elemental Composition;92
7.2.1.4;5.2.1.4 Nitrogen, Sulfur and Oxygen;94
7.2.1.5;5.2.1.5 Isotopic Composition;94
7.2.2;5.2.2 Thermochemical Products;95
7.2.3;5.2.3 Photochemical Products;96
7.2.3.1;5.2.3.1 Evidence for Photochemistry in the Upper Troposphere;96
7.2.3.2;5.2.3.2 Stratospheric Products;98
7.2.4;5.2.4 External Oxygen Flux;100
7.3;5.3 Chemistry;101
7.3.1;5.3.1 Tropospheric Chemistry;101
7.3.1.1;5.3.1.1 Thermochemistry;101
7.3.1.2;5.3.1.2 Photochemistry in the Troposphere;102
7.3.2;5.3.2 Stratospheric Hydrocarbon Chemistry;104
7.3.2.1;5.3.2.1 Chemical Reactions;104
7.3.2.2;5.3.2.2 One-Dimensional Models;105
7.3.2.3;5.3.2.3 Seasonal Variation in 1-D Models;107
7.3.2.4;5.3.2.4 Two-Dimensional Models;109
7.3.3;5.3.3 Oxygen Chemistry;110
7.3.4;5.3.4 Auroral Chemistry;112
7.4;5.4 Summary and Conclusions;112
7.5;References;113
8;Chapter 6 Saturn Atmospheric Structure and Dynamics;119
8.1;6.1 Introduction;119
8.1.1;6.1.1 Saturn’s Place Among Planetary Atmospheres;119
8.1.2;6.1.2 Saturn Science Between the Voyager and Cassini Epochs;121
8.1.3;6.1.3 Questions About Saturn Entering the Cassini Era;122
8.1.4;6.1.4 Scope and Organization of the Chapter;122
8.2;6.2 Observational Inferences About the Deep Atmosphere;123
8.2.1;6.2.1 Saturn’s Rotation Period;123
8.2.2;6.2.2 Convective Heat Flux and Condensation Levels;124
8.2.3;6.2.3 Cassini Probing of the Atmosphere Below Cloud Top;125
8.3;6.3 Observations at and Above the Visible Cloud Top;127
8.3.1;6.3.1 Levels Sensed by Cassini Instruments from Cloud Top to the Stratosphere;127
8.3.2;6.3.2 Albedo Patterns vs. Jets on Saturn vs. Jupiter;128
8.3.3;6.3.3 Cloud LevelWinds and Dynamical Fluxes;129
8.3.4;6.3.4 Thermal Structure and Circulation Above Cloud Level;131
8.3.5;6.3.5 Temporal Variation of the Equatorial Jet;133
8.3.6;6.3.6 Upper Troposphere Temperature Knee: Structure and Seasonality of Solar Heating;135
8.3.7;6.3.7 Stratospheric Circulation;136
8.3.7.1;6.3.7.1 Meridional Circulation;136
8.3.7.2;6.3.7.2 Equatorial Oscillations;136
8.3.8;6.3.8 Potential Vorticity Diagnosis;139
8.4;6.4 Discrete Features as Constraints on Processes and Structure;141
8.4.1;6.4.1 Anti-Cyclonic and Cyclonic Vortices;141
8.4.2;6.4.2 Convective Clouds and Lightning;142
8.4.3;6.4.3 Upper Troposphere Thermal Features and Rossby Waves;146
8.4.4;6.4.4 North Polar Hexagon;147
8.4.5;6.4.5 South Polar Vortex;149
8.4.6;6.4.6 OtherWavelike Features;150
8.5;6.5 Theories and Models of the General Circulation;152
8.5.1;6.5.1 Deep Cylinders vs. Shallow Weather Layers;152
8.5.2;6.5.2 DistinguishingDeep-or-Shallow Structure from Deep-or-Shallow Forcing;153
8.5.3;6.5.3 Models for Jet Pumping;153
8.5.4;6.5.4 Do the Observations Constrain Our Models?;157
8.6;6.6 Discussion;158
8.6.1;6.6.1 Future Modeling Directions;159
8.6.2;6.6.2 Long-Term Observational Needs;160
8.7;References;160
9;Chapter 7 Clouds and Aerosols in Saturn’s Atmosphere;166
9.1;7.1 Introduction;166
9.2;7.2 Expectations fromThermochemical Equilibrium Theory and Photochemistry;167
9.3;7.3 Observational Constraints on Particle Composition and Chromophores;168
9.4;7.4 Aerosol Optical and Physical Properties;170
9.5;7.5 Aerosol Vertical Structure;173
9.5.1;7.5.1 Radiative Transfer Models and Haze Structure;173
9.5.2;7.5.2 Mean Vertical Structure;174
9.5.3;7.5.3 Latitudinal Structure;176
9.5.4;7.5.4 Short-term Changes;176
9.5.5;7.5.5 Seasonal Changes;177
9.5.6;7.5.6 Regional Structure: The Equatorial Jet;177
9.5.7;7.5.7 Regional Structure: The GreatWhite Spot (GWS);179
9.5.8;7.5.8 Regional Structure: The South Polar Vortex;180
9.5.9;7.5.9 Convective Clouds;180
9.6;7.6 Solar Radiation Penetration and Deposition;182
9.7;7.7 Summary and FutureWork;182
9.8;References;183
10;Chapter 8 Upper Atmosphere and Ionosphere of Saturn;185
10.1;8.1 Introduction;185
10.2;8.2 Structure and Composition of the Neutral Upper Atmosphere;185
10.2.1;8.2.1 Determination of Atmospheric Properties from Ultraviolet Occultations;186
10.2.2;8.2.2 Determination of Atmospheric Properties from UVIS Spectra and Emission Maps;189
10.3;8.3 Theoretical and Empirical Models of the Neutral Upper Atmosphere: Chemistry and Atmospheric Transport in the Homopause Region;189
10.4;8.4 Theoretical and Empirical Models of the Upper Atmosphere: Temperature Structure, Energy Balance, and Dynamics;192
10.4.1;8.4.1 Thermal Structure;192
10.4.2;8.4.2 Energy Balance and Dynamics;193
10.5;8.5 Observations of the Ionosphere;195
10.5.1;8.5.1 Radio Occultation Observations of Electron Densities;195
10.5.2;8.5.2 Electron Density Variations Inferred from SEDs;195
10.5.3;8.5.3 Ground Based Observations of H3+ Emission;196
10.6;8.6 Models of Ionospheric Structure, Composition and Temperatures;197
10.6.1;8.6.1 Background Theory and EarlyModels;197
10.6.2;8.6.2 Modern Theory and Time Dependent Models;198
10.6.3;8.6.3 Plasma Temperatures in Saturn’s Ionosphere;201
10.7;8.7 Summary;201
10.8;References;203
11;Chapter 9 Saturn’s Magnetospheric Configuration;206
11.1;9.1 Introduction;206
11.1.1;9.1.1 Pre-Cassini Understanding;206
11.1.2;9.1.2 Major Cassini Discoveries;207
11.1.3;9.1.3 Earth, Jupiter and Saturn;209
11.2;9.2 Magnetic Field;212
11.2.1;9.2.1 Intrinsic Magnetic Field;212
11.2.2;9.2.2 The Magnetodisk;214
11.2.3;9.2.3 Empirical Magnetic FieldModels;215
11.3;9.3 Plasma Sources and Sinks;217
11.3.1;9.3.1 Rings (<3RS);218
11.3.2;9.3.2 Icy Satellites (3RS to 6RS);219
11.3.2.1;9.3.2.1 Enceladus;219
11.3.2.2;9.3.2.2 HC andWC;220
11.3.2.3;9.3.2.3 NC;222
11.3.3;9.3.3 Minor Sources;222
11.3.4;9.3.4 Loss Processes;223
11.3.5;9.3.5 Plasma Density Models;224
11.4;9.4 Magnetospheric Regions;224
11.4.1;9.4.1 Trapped Radiation;224
11.4.2;9.4.2 Ring Current;228
11.4.3;9.4.3 Plasma Sheet;234
11.4.4;9.4.4 Magnetotail;237
11.4.5;9.4.5 GlobalMHD Models;240
11.5;9.5 Ionosphere-Magnetosphere Coupling;240
11.5.1;9.5.1 Radial Transport;240
11.5.2;9.5.2 Corotation, Subcorotation and Corotation Breakdown;243
11.6;9.6 Upstream and SolarWind Boundaries;245
11.6.1;9.6.1 Upstream Conditions;245
11.6.2;9.6.2 Foreshock Region;246
11.6.3;9.6.3 Bow Shock and Magnetosheath;249
11.6.4;9.6.4 Magnetopause;250
11.6.4.1;9.6.4.1 Standoff Distance;250
11.6.4.2;9.6.4.2 Compressibility;250
11.6.4.3;9.6.4.3 Shape;251
11.7;9.7 Some Open Questions;251
11.8;References;252
12;Chapter 10 The Dynamics of Saturn’s Magnetosphere;259
12.1;10.1 Introduction;259
12.2;10.2 Transport of Mass and Energy, and Plasma Flow;259
12.3;10.3 Rotational Modulation;263
12.4;10.4 Magnetic Field Structure and Dynamics;269
12.5;10.5 Magnetotail Dynamics;271
12.6;10.6 Magnetospheric Compression;275
12.7;10.7 Conclusion;277
12.8;References;277
13;Chapter 11 Fundamental Plasma Processes in Saturn’sMagnetosphere;282
13.1;11.1 Introduction;282
13.2;11.2 Plasma–Material Interaction Processes;283
13.2.1;11.2.1 Signatures of Gas and Plasma Sources;283
13.2.1.1;11.2.1.1 Neutral Gas Components;283
13.2.2;11.2.2 Charged Particle and Plasma Interactions with Surfaces;285
13.2.2.1;11.2.2.1 Introduction and Background;285
13.2.2.2;11.2.2.2 Application to Saturn;286
13.2.2.2.1;Surface Radiolysis;286
13.2.2.2.2;Surface Irradiation;286
13.2.2.2.3;Surface Sputtering in Saturn’s Magnetosphere;286
13.2.2.2.4;Radiolytic Production of Molecular Oxygen;286
13.2.3;11.2.3 Charged Particle and Plasma Interactions with Neutral Gas;287
13.2.3.1;11.2.3.1 Introduction and Background;287
13.2.3.2;11.2.3.2 Application to Saturn;287
13.2.3.2.1;Neutral Sources and Predictions;287
13.2.3.2.2;Neutral Loading at Saturn and Jupiter;288
13.2.3.2.3;Charge Exchange;288
13.2.3.2.4;Neutral Scattering;289
13.2.3.2.5;Electron-Induced Processes;289
13.2.3.2.6;Comet-Like Interactions;289
13.2.4;11.2.4 Moon–Magnetosphere Interactions;290
13.2.4.1;11.2.4.1 Introduction and Background;290
13.2.4.1.1;Internal Magnetic Fields;290
13.2.4.1.2;Interaction Environments and Features;291
13.2.4.1.3;Physical Processes;291
13.2.4.2;11.2.4.2 Plasma Absorbing Interactions at Saturn;291
13.2.4.2.1;Cold Plasma Response;291
13.2.4.2.2;Magnetic Field Response;292
13.2.4.2.3;Energetic Particle Response;293
13.2.4.2.4;Special Cases;294
13.2.4.3;11.2.4.3 Mass Loading Interactions at Saturn;294
13.2.4.3.1;Thermal Plasma and Magnetic Field Response;294
13.2.4.3.2;Energetic Particle Response;296
13.3;11.3 Transport;296
13.3.1;11.3.1 Rotational versus Solar-WindDrivers;297
13.3.2;11.3.2 Magnetosphere–Ionosphere Coupling;298
13.3.3;11.3.3 Corotation Lag;299
13.3.4;11.3.4 Centrifugal Interchange Instability;301
13.3.5;11.3.5 The Radial Diffusion Formalism;304
13.4;11.4 Energy Conversion;305
13.4.1;11.4.1 Reconnection;306
13.4.1.1;11.4.1.1 Magnetopause Reconnection;306
13.4.1.1.1;Proxy Studies at Earth;307
13.4.1.1.2;In Situ Studies at Earth;307
13.4.1.1.3;In Situ Studies at Saturn;307
13.4.1.1.4;Discussion/Future Directions;308
13.4.1.2;11.4.1.2 Tail Reconnection;308
13.4.1.2.1;Tail Stretching and the Growth Phase;309
13.4.1.2.2;Dipolarization;309
13.4.1.2.3;Near the Neutral Point;309
13.4.1.2.4;Plasmoid Formation;309
13.4.1.2.5;Discussion/Future Directions;311
13.4.2;11.4.2 Particle Acceleration;311
13.4.2.1;11.4.2.1 Adiabatic Acceleration and Related Processes;311
13.4.2.1.1;Background;311
13.4.2.1.2;Adiabatic Acceleration at Saturn;312
13.4.2.2;11.4.2.2 Pickup Acceleration and Related Processes at Saturn;314
13.4.2.2.1;Background;314
13.4.2.2.2;Pickup Energization at Saturn;315
13.4.2.2.3;Pickup-Associated Electron Acceleration;315
13.4.2.3;11.4.2.3 Other Acceleration Processes;316
13.4.2.3.1;Injection Energization;316
13.4.2.3.2;Miscellaneous Acceleration Mechanisms;317
13.4.3;11.4.3 Current Generation;317
13.4.3.1;11.4.3.1 Background;317
13.4.3.2;11.4.3.2 Force Balance at Jupiter and Saturn;318
13.4.4;11.4.4 Wave Particle Interactions;319
13.4.4.1;11.4.4.1 Background onWave Particle interactions;319
13.4.4.2;11.4.4.2 Background onWaveModes;320
13.4.4.3;11.4.4.3 Application to Cassini;320
13.4.4.3.1;ECH, UHR, and Narrowband Radio Emissions;320
13.4.4.3.2;Whistler-Mode Emissions;323
13.4.4.3.3;Miscellaneous Plasma Waves;324
13.5;11.5 Closing Remarks;325
13.6;References;325
14;Chapter 12 Auroral Processes;333
14.1;12.1 Introduction;333
14.2;12.2 Observations of Auroral Emissions;334
14.2.1;12.2.1 Pre-Cassini Summary;334
14.2.2;12.2.2 Earth-Based Observations Concurrent with Cassini;334
14.2.2.1;12.2.2.1 HST-Cassini Campaigns;334
14.2.2.2;12.2.2.2 Saturn’s Ultraviolet Auroral Morphology;335
14.2.2.3;12.2.2.3 H2 Auroral Spectroscopy;336
14.2.2.4;12.2.2.4 Effects of Auroral Energy Input to the Atmosphere;337
14.2.2.5;12.2.2.5 Ground-Based Observations of Saturn’s IR Aurora;338
14.2.3;12.2.3 Cassini Remote Sensing Observations of Auroral Emissions;339
14.2.3.1;12.2.3.1 UVIS Results;339
14.2.3.2;12.2.3.2 VIMS Results;340
14.2.3.3;12.2.3.3 ISS Results;340
14.2.4;12.2.4 Auroral Radio Emissions;341
14.3;12.3 Magnetospheric Dynamics and the Aurora;347
14.3.1;12.3.1 Response of the Aurora to Solar Wind Input;348
14.3.2;12.3.2 Response of the Aurora to Rotational Dynamics;350
14.4;12.4 In-Situ Measurements;351
14.4.1;12.4.1 Energetic Particles;351
14.4.2;12.4.2 Auroral Currents;358
14.5;12.5 SolarWind-Magnetosphere–Ionosphere Coupling Currents and Their Relation to Saturn’s Aurora;361
14.5.1;12.5.1 Proposed Steady-State Theoretical Framework;361
14.5.2;12.5.2 Time-Dependent Auroral Processes;365
14.6;12.6 Summary;369
14.7;References;370
15;Chapter 13 The Structure of Saturn’s Rings;375
15.1;13.1 Grand Structure of the Rings;375
15.2;13.2 A Ring;377
15.2.1;13.2.1 Satellite Resonance Features;378
15.2.1.1;13.2.1.1 Density and BendingWaves;378
15.2.1.2;13.2.1.2 Outer Edge of the A Ring;381
15.2.2;13.2.2 Satellite Impulse-Driven Features;381
15.2.2.1;13.2.2.1 Wavy Edges of the Encke and Keeler Gaps;381
15.2.2.2;13.2.2.2 SatelliteWakes;382
15.2.3;13.2.3 Self-GravityWakes and Propellers;382
15.2.4;13.2.4 The Inner A Ring;386
15.2.5;13.2.5 Small-Scale Periodic Structures;387
15.3;13.3 B Ring;387
15.3.1;13.3.1 Overview;387
15.3.2;13.3.2 The Inner B Ring (Region B1);389
15.3.3;13.3.3 The Central B Ring (Regions B2 and B3);390
15.3.4;13.3.4 The Outer B Ring (Regions B4 and B5);391
15.3.5;13.3.5 Density and BendingWaves;392
15.3.6;13.3.6 Self-GravityWakes;392
15.3.7;13.3.7 Correlations of Structure with Particle Properties;394
15.4;13.4 The Cassini Division and C Ring;394
15.4.1;13.4.1 Overview;394
15.4.2;13.4.2 Gaps and Ringlets in the Cassini Division;394
15.4.3;13.4.3 DensityWaves in the Cassini Division;397
15.4.4;13.4.4 C Ring Structure;398
15.4.5;13.4.5 Waves and Other Resonant Features in the C Ring;400
15.5;13.5 F Ring;401
15.5.1;13.5.1 Overview;401
15.5.2;13.5.2 Perturbations by Prometheus;402
15.5.3;13.5.3 Jets and Kinematic Spirals;403
15.5.4;13.5.4 Embedded Objects;403
15.5.5;13.5.5 A Narrow Component;405
15.6;13.6 Summary;406
15.6.1;13.6.1 DensityWaves;406
15.6.2;13.6.2 Microstructure of the Rings;407
15.6.3;13.6.3 Vertical Structure;407
15.6.4;13.6.4 Large-Scale Structure;407
15.6.5;13.6.5 Future Prospects;408
15.7;References;408
16;Chapter 14 Dynamics of Saturn’s Dense Rings;413
16.1;14.1 General Theory and Recent Advances;413
16.1.1;14.1.1 Steady-State of a Dense Non-Gravitating Particle Disk;414
16.1.1.1;14.1.1.1 Dissipative Collisions;414
16.1.1.2;14.1.1.2 Shear Stress;414
16.1.1.2.1;Local Shear Viscosity;414
16.1.1.2.2;Non-Local Shear Viscosity and Pressure;415
16.1.1.2.3;Total Shear Viscosity and Pressure;415
16.1.1.3;14.1.1.3 Steady State and Thermal Stability;415
16.1.1.4;14.1.1.4 Mechanical Properties of Particles;416
16.1.1.5;14.1.1.5 Steady State Dynamical Properties;417
16.1.2;14.1.2 Balance Equations for Dense Rings;418
16.1.2.1;14.1.2.1 Kinetic Theory;418
16.1.2.2;14.1.2.2 Hydrodynamics;419
16.1.3;14.1.3 Self-Gravity of the Ring;421
16.1.3.1;14.1.3.1 Gravitational Encounters;422
16.1.3.2;14.1.3.2 Vertical Self-Gravity;422
16.1.3.3;14.1.3.3 GravitationalWakes;422
16.1.3.4;14.1.3.4 Survey of Self-GravityWake Structures;425
16.1.3.5;14.1.3.5 Gravitational Viscosity;425
16.1.3.6;14.1.3.6 Observational Signatures of Self-Gravity Wakes;426
16.2;14.2 Instabilities;429
16.2.1;14.2.1 ViscousOverstability;430
16.2.1.1;14.2.1.1 A Linear Model;430
16.2.1.2;14.2.1.2 Overstability and Self-Gravity;432
16.2.2;14.2.2 Viscous Instability;433
16.2.3;14.2.3 Instabilities due to Ballistic and Electromagnetic Transport;435
16.2.4;14.2.4 Shear Rate Instability;435
16.3;14.3 RingMoon Interactions and Narrow Rings;436
16.3.1;14.3.1 SpiralWaves;436
16.3.1.1;14.3.1.1 Background;436
16.3.1.2;14.3.1.2 Elements of Theory;437
16.3.1.3;14.3.1.3 Advances in Modeling;438
16.3.1.3.1;The Waves Associated with the Co-Orbital Satellites;438
16.3.1.3.2;Power Spectrum Density Methods;438
16.3.1.3.3;Application of the Nonlinear Theory;438
16.3.2;14.3.2 Moonlet Induced Gaps;439
16.3.3;14.3.3 Propellers – the Action of Tiny Moons;440
16.3.4;14.3.4 Dense NarrowRings;443
16.3.4.1;14.3.4.1 Confinement of Narrow Rings;443
16.3.4.2;14.3.4.2 Rigid Precession;444
16.3.4.3;14.3.4.3 Excitation of Eccentricities and Inclinations;444
16.3.4.4;14.3.4.4 Viscous Overstability;444
16.3.4.5;14.3.4.5 Ring Edges;444
16.4;14.4 Size Distribution and Spins of Ring Particles;445
16.4.1;14.4.1 Particle Size Distribution and Its Evolution;445
16.4.1.1;14.4.1.1 Particle Size Distribution Derived From Observations;445
16.4.1.2;14.4.1.2 Accretion of Particles in the Roche Zone;446
16.4.1.3;14.4.1.3 Processes and Models for Particle Size Evolution;448
16.4.2;14.4.2 Particle Spins;449
16.4.2.1;14.4.2.1 Dynamical Studies;449
16.4.2.2;14.4.2.2 Relation to Observations of the Rings’ Thermal Emission;451
16.5;14.5 Open Problems;451
16.6;References;452
17;Chapter 15 Ring Particle Composition and Size Distribution;459
17.1;15.1 Introduction;459
17.2;15.2 Ring Particle Size Distribution;460
17.2.1;15.2.1 Models and Theory;460
17.2.2;15.2.2 Cassini RSS Extinction Observations;462
17.2.3;15.2.3 Model Results;464
17.2.4;15.2.4 Near-Forward Scattered Signal Observations;466
17.2.5;15.2.5 Size Distribution from the Voyager RSS Observations;467
17.2.6;15.2.6 Size Distribution from 28 Sgr Stellar Occultations;469
17.2.7;15.2.7 Size Information from the Excess Variance in Stellar Occultations;470
17.2.8;15.2.8 Summary of Current Knowledge and Limitations;470
17.2.9;15.2.9 Comparison of the Four Main Ring Regions;471
17.2.10;15.2.10 Caveats Regarding Modeling “Ring Particles” vs. “Self-GravityWakes”;472
17.3;15.3 “Propeller” Objects: Shards of the Ring Parent or Locally Grown?;473
17.4;15.4 Ring Particle Composition, Its Radial Variations, and Comparison with Other Icy Objects;474
17.4.1;15.4.1 Observations;474
17.4.2;15.4.2 Global VIMS Ring Spectra and Overall Composition;476
17.4.3;15.4.3 Regional and Phase Angle Variations of VIMS Ring Spectra;476
17.4.4;15.4.4 UVIS Spectra of theMain Ring Regions;479
17.4.5;15.4.5 Radial Profiles of ISS and VIMS Spectral Properties;479
17.4.5.1;15.4.5.1 Radial Profiles of ISS and VIMS Spectral Properties;479
17.4.5.2;15.4.5.2 Particle Albedo Variation from CIRS Ring Temperature Profiles;481
17.4.6;15.4.6 Modeling Individual Particle Properties from Observed Ring Reflectance;483
17.4.6.1;15.4.6.1 Modeling the Layer of Ring Particles as a Whole;483
17.4.6.2;15.4.6.2 Modeling Ring Particle Regoliths;483
17.4.7;15.4.7 Laboratory and ModelWater Abundance and RegolithGrain Size;484
17.4.7.1;15.4.7.1 Water Ice Band Depths fromVIMS Data;484
17.4.7.2;15.4.7.2 Regolith Properties fromCIRS Spectra at Long Thermal InfraredWavelengths;485
17.4.8;15.4.8 GlobalModels of Ring Composition;486
17.4.9;15.4.9 Comparison of Ring Spectral Properties with Other Icy Objects;489
17.5;15.5 Ring Atmosphere and Meteoroid Bombardment;492
17.5.1;15.5.1 Introduction;492
17.5.2;15.5.2 Main Rings;492
17.5.3;15.5.3 Modeling of the Ring Atmosphere;493
17.5.4;15.5.4 Atmosphere-Driven Chemistry on Icy Ring Particle Surfaces;494
17.5.5;15.5.5 The Ring Atmosphere as a Magnetospheric and Atmospheric Source;495
17.5.6;15.5.6 Meteoroid Bombardment, Ring Mass, and Ring Composition;495
17.6;15.6 Summary, Discussion, and Future Directions;496
17.6.1;15.6.1 Summary of Observational Properties;496
17.6.2;15.6.2 Origin – the Big Picture;497
17.6.3;15.6.3 Candidate “UV Absorbers”;499
17.6.4;15.6.4 FutureWork Needing to Be Done;500
17.7;Appendix 15: The Zero-Phase Opposition Effect;501
17.8;References;504
18;Chapter 16 Diffuse Rings;510
18.1;16.1 Introduction;510
18.2;16.2 Pre-Cassini Observations;511
18.3;16.3 Cassini Observations and Current Theories;513
18.3.1;16.3.1 The D Ring;513
18.3.2;16.3.2 The Roche Division;516
18.3.3;16.3.3 Resonant Structures in the D Ring and the Roche Division;516
18.3.4;16.3.4 Faint Ringlets Within Main-Ring Gaps;517
18.3.5;16.3.5 Spokes in the B Ring;518
18.3.6;16.3.6 The G Ring;520
18.3.7;16.3.7 Other Narrow Outer Faint Rings;522
18.3.8;16.3.8 The E Ring;522
18.3.9;16.3.9 Dust Streams;529
18.4;16.4 Summary: Dynamical Connections Between Diffuse Rings;531
18.5;References;532
19;Chapter 17 Origin and Evolution of Saturn’s Ring System;536
19.1;17.1 Introduction;536
19.1.1;17.1.1 New Results on an Old Question;536
19.1.2;17.1.2 Organization of the Chapter;537
19.2;17.2 Basic Observational Constraints and Theoretical Considerations;537
19.2.1;17.2.1 Ring Structure;537
19.2.1.1;17.2.1.1 Ring Particle Sizes;538
19.2.1.2;17.2.1.2 Ring Particle Composition;540
19.2.1.3;17.2.1.3 Mass of Saturn’s Rings;540
19.2.2;17.2.2 Processes in Saturn’s Rings: Simple Considerations;541
19.2.2.1;17.2.2.1 Tidal Forces: the Roche Limit;541
19.2.2.2;17.2.2.2 Collisions: Flattening and Viscous Spreading;541
19.2.2.3;17.2.2.3 Meteoroid Bombardment;542
19.2.2.4;17.2.2.4 Cosmic Recycling;543
19.2.2.5;17.2.2.5 Young or Old Rings?;544
19.2.3;17.2.3 An Overview of Possible Scenarios for the Origin of the Main Rings;546
19.2.4;17.2.4 Beyond the Paradox?;547
19.3;17.3 Evolution of theMain Rings;547
19.3.1;17.3.1 Meteoritic Bombardment and Ballistic Transport;548
19.3.1.1;17.3.1.1 Principles;548
19.3.1.2;17.3.1.2 Dynamical Evolution;549
19.3.1.3;17.3.1.3 Spectral Evolution;550
19.3.2;17.3.2 Limited Accretion;551
19.3.2.1;17.3.2.1 Gravitational Instability;553
19.3.2.2;17.3.2.2 Tidally Modified Accretion;553
19.3.2.3;17.3.2.3 Surface Sticking;554
19.3.2.4;17.3.2.4 Accretion of Small Embedded Satellites?;555
19.3.3;17.3.3 Collisional Cascade;556
19.3.4;17.3.4 Ring–Moon Interactions;557
19.3.5;17.3.5 The Long Term Evolution of Saturn’s Main Rings;558
19.4;17.4 Scenarios for Origin of the Main Rings;558
19.4.1;17.4.1 Remnant from Saturn’s Sub-nebula Disk?;558
19.4.1.1;17.4.1.1 Satellite Formation;559
19.4.1.2;17.4.1.2 Implanting the Ring System;559
19.4.1.3;17.4.1.3 Collapse and Cooling of the Envelope;559
19.4.1.4;17.4.1.4 The Role of Turbulence;560
19.4.1.5;17.4.1.5 Caveats;560
19.4.2;17.4.2 Debris from a Destroyed Satellite?;561
19.4.2.1;17.4.2.1 Bringing and Keeping a Satellite in the Roche Zone;561
19.4.2.2;17.4.2.2 Destruction of the Satellite;562
19.4.3;17.4.3 Debris from Tidally Disrupted Comets;563
19.4.4;17.4.4 A Conclusion?;565
19.5;17.5 Saturn’s F Ring: Processes and Origin;565
19.5.1;17.5.1 Characteristics of the F Ring Relevant for Its Origin and Evolution;565
19.5.2;17.5.2 Processes atWork in the F Ring;566
19.5.3;17.5.3 Origin and Evolution of Saturn’s F Ring;567
19.6;17.6 Diffuse Rings: Processes and Origins;567
19.7;17.7 Conclusions;569
19.8;References;570
20;Chapter 18 The Thermal Evolution and Internal Structure of Saturn’s Mid-SizedIcy Satellites;575
20.1;18.1 Introduction;575
20.2;18.2 Satellite Properties;577
20.2.1;18.2.1 Size and Shape;577
20.2.2;18.2.2 Density;577
20.2.3;18.2.3 Porosity;579
20.2.4;18.2.4 Initial Composition;580
20.2.4.1;18.2.4.1 Volatile Composition;580
20.2.4.2;18.2.4.2 Rock Composition;581
20.2.4.3;18.2.4.3 Rhea’s Gravitational Field;581
20.3;18.3 Sources of Heat;583
20.3.1;18.3.1 Heating by Radioactivity;584
20.3.2;18.3.2 Tidal Heating;584
20.3.2.1;18.3.2.1 Despinning;585
20.3.2.2;18.3.2.2 Orbital Eccentricity;586
20.3.3;18.3.3 Heat from the Gravitational Field;586
20.3.3.1;18.3.3.1 Accretion;586
20.3.3.2;18.3.3.2 Internal Conversion of Gravitational Potential into Heat;588
20.4;18.4 Thermal Transfer;588
20.4.1;18.4.1 Heat Transfer by Conduction;588
20.4.2;18.4.2 Heat Transfer by Convection;588
20.4.3;18.4.3 Onset of Convection;591
20.4.4;18.4.4 Convective Evolution and an Example;592
20.5;18.5 Constraints on Thermal Parameters;593
20.5.1;18.5.1 Ice Thermal Conductivity;593
20.5.2;18.5.2 Rock Thermal Conductivity;593
20.5.3;18.5.3 Effect of Porosity;594
20.6;18.6 Structural Evolution;594
20.6.1;18.6.1 Porosity Evolution;594
20.6.2;18.6.2 Melting and Differentiation;595
20.6.3;18.6.3 Long-Term Evolution of a Rock Core;595
20.7;18.7 Model Studies of Thermal and Dynamical Evolution;596
20.7.1;18.7.1 Effect of Initial Composition;596
20.7.1.1;18.7.1.1 Rock-Rich Models;597
20.7.1.2;18.7.1.2 Rock-Poor Models;597
20.7.2;18.7.2 Global Evolution;597
20.7.2.1;18.7.2.1 Assessing the State of Differentiation of an Icy Satellite;597
20.7.2.2;18.7.2.2 Evolution of the Lithosphere;598
20.7.2.3;18.7.2.3 Shape Evolution;599
20.7.2.4;18.7.2.4 Age of Iapetus;599
20.7.2.5;18.7.2.5 Iapetus’ Equatorial Ridge;600
20.8;18.8 Other Satellites;601
20.8.1;18.8.1 Phoebe;601
20.8.2;18.8.2 Mimas, Tethys and Dione;602
20.9;18.9 At the Frontiers: Space, Laboratory, Processes, and Modeling;603
20.9.1;18.9.1 Space;603
20.9.2;18.9.2 Laboratory Data Needed;603
20.9.3;18.9.3 Processes;604
20.9.4;18.9.4 Modeling;604
20.10;18.10 Concluding Remarks;604
20.11;Appendix: Glossary of Symbols;605
20.12;References;605
21;Chapter 19 Icy Satellites of Saturn: Impact Cratering and Age Determination;611
21.1;19.1 Introduction: Understanding of Saturnian Impact Crater Populations Through the Voyager Era;611
21.2;19.2 Impactor Populations;613
21.3;19.3 Heavy Bombardments;615
21.4;19.4 Cratering Chronologies;616
21.5;19.5 Impact Physics and Scaling Laws;617
21.6;19.6 Predicted Cratering Rates by Comets;619
21.6.1;19.6.1 Implications for Catastrophic Disruption;623
21.7;19.7 Observed Crater Statistics and Interpretation;624
21.8;19.8 Conclusions;628
21.9;References;629
21.10;Icy Satellites of Saturn: Impact Cratering and Age Determination;611
22;Chapter 20 Icy Satellites: Geological Evolution and Surface Processes;634
22.1;20.1 Introduction;634
22.2;20.2 Cassini’s Exploration of Saturn’s Icy Satellites;636
22.3;20.3 Morphology, Geology and Topography;637
22.3.1;20.3.1 Craters;639
22.3.2;20.3.2 Tectonics;639
22.3.3;20.3.3 Cryovolcanism;647
22.4;20.4 Composition and Alteration of Surface Materials;648
22.4.1;20.4.1 DarkMaterial;651
22.4.2;20.4.2 Iapetus’ Hemispheric Dichotomy;653
22.4.3;20.4.3 Surface Alterations and Photometry;655
22.5;20.5 Constraints on the Top-Meter Structure and Composition by Radar;660
22.5.1;20.5.1 Radar-Optical Correlations;661
22.5.2;20.5.2 Wavelength Dependence;662
22.5.3;20.5.3 Iapetus Radar Image;664
22.6;20.6 Geological Evolution;665
22.7;20.7 Conclusions;669
22.8;References;670
23;Chapter 21 Enceladus: An Active Cryovolcanic Satellite;679
23.1;21.1 Cassini’s Exploration of Enceladus;679
23.2;21.2 Interior and Tidal Heating;681
23.2.1;21.2.1 Introduction;681
23.2.2;21.2.2 Bulk Structure;682
23.2.2.1;21.2.2.1 Observational Constraints;682
23.2.2.2;21.2.2.2 Indirect Arguments;683
23.2.2.3;21.2.2.3 Discussion and Summary;683
23.2.3;21.2.3 Interior Composition and Chemistry;684
23.2.4;21.2.4 Heat Production and Tides;684
23.2.5;21.2.5 Thermal Structure;686
23.2.6;21.2.6 Evolution Through Time;687
23.2.7;21.2.7 Summary and FutureWork;689
23.3;21.3 Geology;689
23.3.1;21.3.1 Introduction;689
23.3.2;21.3.2 Major Terrains: Nature and Global Distribution;690
23.3.2.1;21.3.2.1 Cratered Plains:;690
23.3.2.2;21.3.2.2 Eastern (Trailing) Hemisphere Fractured Plains;690
23.3.2.3;21.3.2.3 Western (Leading) Hemisphere Fractured Plains;693
23.3.2.4;21.3.2.4 South Polar Terrain (SPT);693
23.3.2.5;21.3.2.5 Tiger Stripes;695
23.3.3;21.3.3 Surface Age Distribution Through Crater Counting;697
23.3.4;21.3.4 Global Tectonics and Possible Rotational Changes;697
23.4;21.4 The Surface: Composition and Processes;698
23.4.1;21.4.1 Surface Composition;698
23.4.1.1;21.4.1.1 Water Ice, and Its Spatial Variability;698
23.4.1.2;21.4.1.2 Minor Constituents;699
23.4.2;21.4.2 Surface Processes;700
23.5;21.5 Plumes and System Interaction;701
23.5.1;21.5.1 Introduction;701
23.5.2;21.5.2 Observations;701
23.5.2.1;21.5.2.1 Imaging Science Subsystem (ISS);701
23.5.2.2;21.5.2.2 Composite Infrared Spectrometer (CIRS);703
23.5.2.3;21.5.2.3 Ultraviolet Imaging Spectrometer (UVIS);703
23.5.2.4;21.5.2.4 Ion and Neutral Mass Spectrometer (INMS);706
23.5.2.5;21.5.2.5 Cosmic Dust Analyzer (CDA);707
23.5.2.6;21.5.2.6 Visual and Infrared Mapping Spectrometer (VIMS);707
23.5.2.7;21.5.2.7 Magnetometer (MAG) and Cassini Plasma Spectrometer (CAPS);708
23.5.2.8;21.5.2.8 Groundbased Observations;708
23.5.3;21.5.3 Plume Models;708
23.5.3.1;21.5.3.1 Transfer of Heat to the Surface;708
23.5.3.2;21.5.3.2 Plume Dynamics and Particle Formation;710
23.5.3.3;21.5.3.3 Plume Composition;711
23.5.4;21.5.4 SystemInteraction;712
23.5.5;21.5.5 Variability of the Activity;712
23.5.6;21.5.6 Conclusions: The Nature of the Plume Source;713
23.6;21.6 Biological Potential of Enceladus;713
23.7;21.7 Summary and Future Exploration;715
23.8;List of Acronyms;716
23.9;References;717
24;Chapter 22 The Cassini Extended Mission;721
24.1;22.1 Introduction;721
24.2;22.2 EquinoxMission Design Overview;722
24.3;22.3 The EquinoxMission Science Objectives;723
24.3.1;22.3.1 Icy Satellite Objectives;724
24.3.2;22.3.2 Magnetospheric Objectives;724
24.3.3;22.3.3 Rings Objectives;724
24.3.4;22.3.4 Saturn Objectives;725
24.3.5;22.3.5 Titan Objectives;725
24.4;22.4 Operational and Safety Constraints;725
24.5;22.5 Tour Design and Development Process;726
24.6;22.6 The EquinoxMission Trajectory;728
24.6.1;22.6.1 DetailedDescription of EM Trajectory Phases;733
24.6.1.1;22.6.1.1 High Inclination Phase (T45–T51);733
24.6.1.2;22.6.1.2 8-Day Pi-Transfer (T51–T52);734
24.6.1.3;22.6.1.3 Saturn Equinox (T52–T62);734
24.6.1.4;22.6.1.4 Icy Satellites and Ansa-to-Ansa Occultations (T62–T68);734
24.6.1.5;22.6.1.5 High Northern Titan Groundtracks (T68–T70);736
24.7;22.7 Beyond the EquinoxMission;736
24.7.1;22.7.1 Cassini End-of-Mission;738
24.8;References;739
25;Chapter 23 Saturn’s Exploration Beyond Cassini-Huygens;741
25.1;23.1 Introduction;741
25.2;23.2 Saturn’s Interior;742
25.3;23.3 Structure and Evolution of Low-Density Giant Planets;743
25.4;23.4 Saturn’s Atmospheric Composition;744
25.5;23.5 Saturn’s Atmospheric Dynamics;745
25.6;23.6 Saturn’sMagnetosphere;748
25.7;23.7 Saturn’s Rings;749
25.7.1;23.7.1 Direct Imaging of Particle Size Distribution;750
25.7.2;23.7.2 Microstructuration;750
25.7.3;23.7.3 Rings Thickness;751
25.7.4;23.7.4 Chemical Composition: the Mystery of Silicates;751
25.7.5;23.7.5 Rings’Mass;751
25.8;23.8 Saturn and the Formation of the Solar System;751
25.9;23.9 TheMeans of Saturn’s Future Exploration;753
25.9.1;23.9.1 Flyby;753
25.9.2;23.9.2 Orbiter;753
25.9.3;23.9.3 Probes;754
25.9.4;23.9.4 Microprobe in Saturn’s Rings;754
25.9.5;23.9.5 Observations from 1AU;754
25.10;23.10 Conclusions;755
25.11;References;755
26;Chapter 24 Cartographic Mapping of the Icy Satellites Using ISS and VIMS Data;758
26.1;24.1 Introduction;758
26.2;24.2 Shapes and Sizes of the Saturnian Satellites;759
26.3;24.3 Global Basemaps Derived from Cassini-ISS Images;761
26.3.1;24.3.1 Data Processing;761
26.3.2;24.3.2 Coordinate System;761
26.3.3;24.3.3 Basemaps;761
26.4;24.4 High-Resolution Atlases;761
26.5;24.5 Compositional Maps Derived from Cassini-VIMS Data;765
26.5.1;24.5.1 Data Processing;765
26.5.2;24.5.2 VIMS Composition Map of Dione;766
26.5.3;24.5.3 VIMS Composition Map of Rhea;771
26.5.4;24.5.4 VIMS Composition Map of Enceladus;771
26.6;24.6 FutureWork;771
26.7;References;775
27;Appendix: The Cassini Orbiter, Behind the Scenes;777
28;Index;789