Regular moon

At least four of the nine likeliest dwarf planets also host regular moon systems: Pluto, Eris, Haumea, and Orcus.

As gas inflow into the parent planet begins to end, the effects of gas-induced migration decrease, allowing for a final generation of moons to survive.

[2] In contrast, Earth's Moon and Pluto's five satellites are thought to have originated from giant impacts between two protoplanets early in the Solar System's history.

Such resonances can excite the eccentricity and inclination of participating moons, leading to appreciable tidal heating which can sustain geological activity.

Several regular moons, such as Europa, Titan, and Enceladus are known to host global subsurface oceans of liquid water, maintained by tidal heating from their respective parent planets.

[19][20][21] These subsurface oceans can drive a variety of geological processes, including widespread cryovolcanism, resurfacing, and tectonics, acting as reservoirs of 'cryomagma' which can be erupted onto a moon's surface.

The sparse atmospheres of Europa, Ganymede, and Callisto are composed largely of oxygen sputtered off from their icy surfaces due to space weathering.

[29][30] One regular moon, Titan, hosts a dense atmosphere dominated by nitrogen as well as stable hydrocarbon lakes on its surface.

The complex interactions between Titan's thick, hazy atmosphere, its surface, and its 'hydrocarbon cycle' have led to the creation of many unusual features, including canyons and floodplains eroded by rivers, possible karst-like topography, and extensive equatorial dune fields.

[13] The four small circumbinary moons of Pluto, which are similarly elongated, also rotate chaotically under the influence of Charon and generally have very high axial tilts.

Results for Namaka were less clear, potentially pointing towards a slower rotational period or a pole-on configuration, with a significant axial tilt relative to its orbital plane.

[37] Escaping ions from the plasma torus are responsible for Jupiter's unusually extensive magnetosphere, generating an internal pressure which inflates it from within.

Due to their ability to support large internal volumes of liquid water, regular moons of the outer Solar System are of particular interest to scientists as targets in the search for extraterrestrial life.

[39][40][41][42] As a result, dedicated missions to investigate the nature and potential habitability of several regular moons' internal oceans have been proposed and launched.