Rhea Archives

Artist’s impression of the simulations conducted in this research. Jupiter (lower left) has a strong magnetic field which creates a cavity in its circumplanetary disk. Saturn (upper right) lacks a strong magnetic field so its circumplanetary disk evolves without a cavity. Credit: Yuri I. Fujii/L-INSIGHT [Kyoto University], Illustrator: Shinichiro Kinoshita

Astrogeology, Callisto, Enceladus, Europa, Ganymede, Gas Giants, Icy Worlds, Io, Jupiter, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Rhea, Saturn, Titan, Water/Hycean Worlds & Oceanography

How Jupiter Cultivated More Large Moons Than Saturn

by Keith CowingApril 8, 2026April 8, 2026

The two largest planets in our Solar System, Jupiter and Saturn, also have the largest satellite systems, or the most moons. At present, Jupiter’s reported moon count stands at more […]

Sketch of the MT strategy, highlighting the dynamical models used in the distinct phases of the tour. -- math.DS

Biosignatures & Paleobiology, Dione, Enceladus, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mimas, Missions & Hardware, Press Release, Rhea, Saturn, Tethys, Water/Hycean Worlds & Oceanography

Low-Energy and Low-Thrust Exploration Tour of Saturnian Moons with Full Lunar Surface Coverage

by Keith CowingMarch 11, 2026March 11, 2026

This study presents the trajectory design for a mission touring Saturn’s Inner Large Moons (Rhea, Dione, Tethys, Enceladus, and Mimas) engineered to meet observational requirements, including full surface coverage, while […]

Major icy bodies in the Solar System, with the Earth’s moon to scale. The images are shown at the proper relative size. From NASA’s Planetary Photojournal (https://photojournal.jpl.nasa.gov/), Earth’s Moon (PIA00302), Europa (PIA00502), Ganymede (PIA00716), Callisto (PIA03456), Mimas (PIA06258), Enceladus (PIA06254), Tethys (PIA07738), Dione (PIA08256), Rhea (PIA08256), Titan (PIA08256), Hyperion (PIA07740), Iapetus (PIA08384), Phoebe (PIA06064), Miranda (PIA18185), Ariel (PIA01534), Umbriel (PIA00040), Titania (PIA01979), Oberon (PIA00034), Triton (PIA00317), Pluto (PIA19952). -- astro-ph.EP

Ariel, Astrogeology, Callisto, Ceres, Charon, Dione, Enceladus, Europa, Ganymede, Iapetus, Ice Giant, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mimas, Miranda, Missions & Hardware, Moon, Oberon, Phoebe, Pluto, Polar / Alpine Expeditions, Rhea, Status Report, Tethys, Titan, Titania, Triton, Umbriel, Water/Hycean Worlds & Oceanography

Icy Worlds: Moons And Dwarf Planets

by Keith CowingDecember 1, 2025December 1, 2025

In the outer solar system beyond Jupiter, water ice is a dominant component of planetary bodies, and most solid objects in this region are classified as icy bodies.

The continuum-divided spectra of the Saturnian satellites, in the region of the O-D absorption. The red line shows a gaussian fit to the data using a fixed width. Most satellites have separate measurements for the leading and trailing hemispheres, but Hyperion and Phoebe, which are not synchronously rotating, only have single measurements. The O-D absorption is robustly detected at nearly every satellite. -- astro-ph.EP

Dione, Hyperion, Iapetus, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mimas, Phoebe, Rhea, Saturn, Status Report

Deuterated Water Ice On The Satellites Of Saturn

by Keith CowingOctober 17, 2025October 17, 2025

The deuterium to hydrogen ratio in water ice in a planetary body carries important information on the history of water processing and delivery in the protostellar nebula.

An average of the continuum-removed spectra of the leading and trailing hemispheres of Mimas and Tethys and the leading hemispheres of Dione and Rhea, in black, and of the trailing hemispheres of Dione and Rhea, in red. The lines at the bottom show measured wavelengths of CO2 in different states, including in pure crystalline form and trapped as clathrate in crystalline water ice (Oancea et al. 2012), trapped in amorphous ice (Sandford & Allamandola 1990; G´alvez et al. 2008) and physisorbed onto minerals (Hibbitts & Szanyi 2007), which can lead to a wide range of wavelengths. The shorter wavelength 4.2487 µm line associated with the darker hemispheres of Dione and Rhea appears to have no corresponding absorption in the 2.7 µm region. -- astro-ph.EP

Dione, Enceladus, Hyperion, Iapetus, Icy Worlds, Mimas, Phoebe, Rhea, Saturn, Status Report, Tethys

A JWST Study Of CO2 On The Satellites Of Saturn

by Keith CowingOctober 6, 2025October 6, 2025

Solid state CO2 has been detected throughout the outer solar system, even at temperatures where crystalline CO2 is unstable, requiring that the CO2 be trapped in a separate host material.