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From page 299... ... 11 Question 8: Circumplanetary Systems What processes and interactions establish the diverse properties of satellite and ring systems, and how do these systems interact with the host planet and the external environment? Circumplanetary systems -- where a system of moons and/or rings orbit a central body -- are seen throughout the solar system, and in some cases are akin to mini-solar systems with numerous and varied orbiting bodies (Figure 11.1) Read the entire page →
From page 300... ... FIGURE 11.1 A selection of circumplanetary systems of the solar system. Distances are normalized to the size of each primary body. Read the entire page →
From page 301... ... Q8.1a What Processes Have Led to the Diversity of Bulk Properties of Satellite and Ring Systems? The regular ring-moon systems of the giant planets (i.e., the rings and moons orbiting in or near the planet's equatorial plane) Read the entire page →
From page 302... ... innermost moon or moons grew from material expanding from a massive initial ring, perhaps with rocky "kernels" within Saturn's rings accreting outer layers of ice (e.g., Canup 2010; Charnoz et al. Read the entire page →
From page 303... ... and Spohn 2004; de Kleer et al. Read the entire page →
From page 304... ... Q8.2 HOW DO TIDES AND OTHER ENDOGENIC PROCESSES SHAPE PLANETARY SATELLITES? A host of processes beneath the surfaces of planetary satellites shape their diverse properties and evolution over time (Figure 11.3) Read the entire page →
From page 305... ... Q8.2a How and Where Is Tidal Heat Dissipated Within Circumplanetary Systems? As a moon orbits its parent world, it is distorted by tides. Read the entire page →
From page 306... ... in feature types and distributions. For example, Europa possesses "cycloids," arcuate fractures that can be explained by diurnal tidal stresses (e.g., Rhoden et al. Read the entire page →
From page 307... ... freeze, they become pressurized and may fracture the overlying ice shell to allow ocean infiltration. In large ocean worlds (e.g., Ganymede and Titan) Read the entire page →
From page 308... ... heat closer to the surface -- as in Earth) or "heat pipe" volcanism (where melt rises to the surface, transporting heat with it -- as in Io) Read the entire page →
From page 309... ... ● Characterize the current orbital evolution of planetary satellite systems across the solar system (including Earth, Jupiter, Saturn, Uranus, and Neptune) , and determine if they are in thermal equilibrium, by measuring how the satellite orbits are currently evolving, how their host planet responds to satellite tides (including phase lag) Read the entire page →
From page 310... ... Q8.3 WHAT EXOGENIC PROCESSES MODIFY THE SURFACES OF BODIES IN CIRCUMPLANETARY SYSTEMS? Satellite surface landforms and composition provide a record of the processes that shaped each of them, key to understanding their formation and evolution. Read the entire page →
From page 311... ... data to help constrain outer solar system chronology, as some surfaces appear to be quite old, perhaps primordial. Future missions could determine whether unseen terrains on the satellites of the ice giants are consistent with known processes, features and statistics. Read the entire page →
From page 312... ... Q8.3d What Causes the Global-Scale Asymmetries Observed on Moons in Circumplanetary Systems? On tidally locked satellites, the surface can be geographically divided between the nearside (i.e., the planet-facing hemisphere) Read the entire page →
From page 313... ... ● Determine how radiation affects materials in the atmospheres and on the surfaces of planetary satellites, and characterize the associated chemical pathways and yields with laboratory studies of relevant materials, at relevant conditions. Read the entire page →
From page 314... ... belts (Figure 11.5, top panel) Read the entire page →
From page 315... ... FIGURE 11.5 Top panel: Saturn's radiation belts as structured by the rings and inner moons, with gaps due to the absorption of energetic protons by the moons and rings, and with the highest-energy (giga-electron volt) protons confined to radial distances inside the main rings (inset) Read the entire page →
From page 316... ... Strategic Research for Q8.4 ● Quantify material sources, sinks, and mass transport between Jupiter's magnetosphere and moons with in situ magnetic field and plasma measurements. ● Characterize the magnetospheric interactions between Uranus and Neptune's atmosphere, moons, and rings with observations of planetary aurorae, measurements of satellite and ring exospheres and ionospheres, in situ measurements of the global distribution of the plasma composition, density, velocity and temperature, neutral density and composition, and charged dust in both the orbital plane of the moons and rings and at high inclinations. Read the entire page →
From page 317... ... speeds where aggregation transitions to fragmentation. On the other hand, more dynamic regions of the rings where parameters like density or vertical extent change rapidly due to external forces can reveal how changes in one aspect of the dynamical environment can affect other particle properties. Read the entire page →
From page 318... ... Q8.5c What Is the Life-Cycle of Planetary Rings? Recent measurements of the total mass of Saturn's rings and the mass flux between those rings and the planet indicate that the composition and mass of Saturn's rings may change substantially on timescales of hundreds of millions of years, which is much shorter than the age of the solar system (Waite et al. Read the entire page →
From page 319... ... ● Elucidate the origin of Jupiter, Saturn, Uranus and Neptune's small regular satellites and ring-moons, and their relationship and interactions with their rings, by measuring their composition and structure. ● Characterize the present-day evolution of Jupiter, Saturn, Uranus, and Neptune's rings by measuring the mass flux and composition flowing into and out of the rings. Read the entire page →
From page 320... ... Cable, M Read the entire page →
From page 321... ... Hemingway, D., L Read the entire page →
From page 322... ... Roussos, E., P Kollmann, N Read the entire page →
From page 323... ... Q9 PLATE: Earth, viewed from above the Moon's surface by the Lunar Reconnaissance Orbiter in 2015. Read the entire page →

From page 299...

... 11 Question 8: Circumplanetary Systems What processes and interactions establish the diverse properties of satellite and ring systems, and how do these systems interact with the host planet and the external environment? Circumplanetary systems -- where a system of moons and/or rings orbit a central body -- are seen throughout the solar system, and in some cases are akin to mini-solar systems with numerous and varied orbiting bodies (Figure 11.1)