Two-dimensional temperature map of the disk after 280 kyr of evolution. The averaged trajectories of particles over this period, plotted along the 𝑟 and 𝑧 axes, are shown in white. The panels present the trajectories of particles with sizes of 1 cm and 1 𝜇m, released at initial disk temperatures of 20 K (panels a and b) and 80 K (panels c and d). Green triangles indicate the initial positions of the particles, while green crosses mark their final positions. In each panel, the detailed trajectory of an individual particle is highlighted within the square on the right. -- astro-ph.EP

Astrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Callisto, Europa, Ganymede, Icy Worlds, Imaging & Spectroscopy, Io, Jupiter, Status Report

Delivery Of Complex Organic Molecules To The System Of Jupiter

by Keith CowingFebruary 20, 2026February 20, 2026

Complex organic molecules are key markers of molecular diversity, and their formation conditions in protoplanetary disks remain an active area of research. These molecules have been detected on a variety […]

Temperature profiles of the CPD at t = 50, 100, 150, and 200 kyr of its evolution. The formation of COMs by thermal processing occurs in the temperature range from 80 K (blue dashed line) to 260 K (red dashed line). At 150 kyr of evolution, a cold region appears in the model, with temperatures too low to support COM formation by thermal processing. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Callisto, Cryobiology, Europa, Ganymede, Habitable Zones, Ice Giant, Io, Jupiter, Missions & Hardware, Status Report

Formation and Survival of Complex Organic Molecules in the Jovian Circumplanetary Disk

by Keith CowingFebruary 19, 2026February 19, 2026

Europa, Ganymede, and Callisto are key targets in the search for habitability due to the potential presence of subsurface oceans. Detecting complex organic molecules (COMs), essential for prebiotic chemistry, is […]

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Callisto, Europa, Ganymede, Icy Worlds, Io, Jupiter, Press Release

The Water Makeup Of Jupiter’s Galilean Moons Was Set At Birth

by Keith CowingJanuary 20, 2026January 20, 2026

While Io, the most volcanically active moon in the solar system, appears completely dry and devoid of water ice, its neighbor Europa is thought to harbor a vast global ocean […]

Schematic of the circum-Jovian decretion disk. Gas and dust from the circumsolar accretion disk are subsumed into the Jovian disk from approximately one hydrostatic scale height via meridional flows, and move outward beyond the magnetospheric truncation radius. Decretion M˙ is driven by turbulence manifesting as a macroscopic viscosity, and parametrized by the Shakura-Sunyaev α parameter. The four Galilean moons are envisioned to form beyond the ice-line and pressure bump, and undergo Type-I migration inwards. The bump serves as a migration trap, preventing Callisto from convergent migration into resonance with Io, Europa, and Ganymede. -- astro-ph.EP

Callisto, Europa, Ganymede, Icy Worlds, Io, Jupiter, Status Report

Callisto’s Nonresonant Orbit As An Outcome Of Circum-Jovian Disk Substructure

by Keith CowingJanuary 9, 2026January 9, 2026

The Galilean moons of Io, Europa, and Ganymede exhibit a 4:2:1 commensurability in their mean motions, a configuration known as the Laplace resonance.

Surviving rapid inward orbital migration is a crucial aspect of formation models for the Jupiter's Galilean moons. (Source)

Callisto, Europa, Ganymede, Icy Worlds, Io, Jupiter, Status Report

Not Just Gas: How Solid-Driven Torques Shaped the Migration of the Galilean Moons

by Keith CowingDecember 31, 2025December 31, 2025

The primary aim of this study is to investigate the orbital migration of the Galilean moons by incorporating self-consistent solid dynamics in circumjovian disk models. We perform two-fluid simulations using […]

[RIGHT Io [LEFT] Europa -- NASA JPL source

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Europa, Icy Worlds, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Water/Hycean Worlds & Oceanography

On The Divergent Evolution Of Io And Europa As Primordial Ocean Worlds

by Keith CowingDecember 22, 2025December 22, 2025

Galilean moons exhibit a decrease in bulk density with distance from Jupiter, which may reflect differences in evolutionary paths and water loss.

Magnetospheric convection timescale shows a positive correlation with the tidal heating rate. This suggests that exoplanets which are well-positioned for plasma torus construction will generally also receive the necessary tidal power to drive volcanism. This plot includes the 13 terrestrial exoplanets plotted in Figures 1 and 3 which had nonzero orbit eccentricities and orbited within their host stars’ Alfv´en radii, marked on all figures as “high-priority targets”. GJ 367 b is considered the highest priority target due to its high tidal heating power and long magnetospheric convection timescale. The values of τ presented here are the same as in Figure 3. Color indicates the V magnitude of the system which is indicative of favorability for UV-optical spectroscopy. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Io, Lava / magma ocean / Volcanic Worlds, Status Report

Constraining Ongoing Volcanic Outgassing Rates and Interior Compositions of Extrasolar Planets with Mass Measurements of Plasma Tori

by Keith CowingJune 12, 2025June 12, 2025

We present a novel method of constraining volcanic activity on extrasolar terrestrial worlds via characterization of circumstellar plasma tori.

A massive hotspot — larger the Earth’s Lake Superior — can be seen just to the right of Io’s south pole in this annotated image taken by the JIRAM infrared imager aboard NASA’s Juno on Dec. 27, 2024, during the spacecraft’s flyby of the Jovian moon. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

Astrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Press Release

Juno Spots The Most Powerful Volcanic Activity On Io To Date

by Keith CowingJanuary 29, 2025January 29, 2025

Even by the standards of Io, the most volcanic celestial body in the solar system, recent events observed on the Jovian moon are extreme.

The north polar region of Jupiter’s volcanic moon Io was captured by NASA’s Juno during the spacecraft’s 57th close pass of the gas giant on Dec. 30, 2023. Data from recent flybys is helping scientists understand Io’s interior. Credit: Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing by Gerald Eichstädt

Astrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Io, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Press Release

How Io Became The Most Volcanic Body In Our Solar System

by Keith CowingDecember 26, 2024

Scientists with NASA’s Juno mission to Jupiter have discovered that the volcanoes on Jupiter’s moon Io are each likely powered by their own chamber of roiling hot magma rather than […]

A schematic diagram of the sulfur cycle on the icy Galilean moons. Not all processes operate on all moons and the circles with E, G, and C indicate which processes seem to be more restricted to Europa, Ganymede, and Callisto, respectively. Ice radiolysis happens on all icy surfaces and reactions of radiolytically produced H2SO4 can transform brine salts to sulfates. Only for Europa and Callisto the subsurface ocean is likely to be in contact with the rocky ocean floor but not for Ganymede, where massive dense ice layers prevents ongoing exchange of the subsurface with the silicates. The ocean compositions seem to be all quite similar in the beginning, and Ganymede’s ocean might be the oldest ur-ocean remaining since isolation by dense ice. Subsurface oceans on Europa and Callisto can evolve depending on silicate mantle outgassing into the oceans which may increase salinity over time. On Europa acidification from radiolytically produced H2SO4 may happen, which could lead to an ocean with compositional gradients and pH and development of a halocline. This diagram does not claim completeness and is an attempt to summarize observations, ideas and interpretations. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Enceladus, Europa, Ganymede, Gas Giants, Icy Worlds, Imaging & Spectroscopy, Io, Jupiter, Mapping, Geodesy, Cartography, Bathymetry, Neptune, Saturn, Status Report, Titan, Uranus

Sulfur in the Giant Planets, their Moons, and Extrasolar Gas Giant Planets

by Keith CowingOctober 18, 2024October 18, 2024

We review sulfur chemistry of the gas giant planets and their moons where sulfur compounds are observed. The major S-bearing gas in the upper atmospheres of the giant planets is […]

Io

Delivery Of Complex Organic Molecules To The System Of Jupiter

Formation and Survival of Complex Organic Molecules in the Jovian Circumplanetary Disk

The Water Makeup Of Jupiter’s Galilean Moons Was Set At Birth

Callisto’s Nonresonant Orbit As An Outcome Of Circum-Jovian Disk Substructure

Not Just Gas: How Solid-Driven Torques Shaped the Migration of the Galilean Moons

On The Divergent Evolution Of Io And Europa As Primordial Ocean Worlds

Constraining Ongoing Volcanic Outgassing Rates and Interior Compositions of Extrasolar Planets with Mass Measurements of Plasma Tori

Juno Spots The Most Powerful Volcanic Activity On Io To Date

How Io Became The Most Volcanic Body In Our Solar System

Sulfur in the Giant Planets, their Moons, and Extrasolar Gas Giant Planets

Global Genome Atlas Reveals Hidden Life In Lakes

Assessing the Preservation of Polysaccharides from a Sea-Ice Bacterium Through Analog Icy Moon Plume Ejection

AstroGenesis: A Domain-Specific Multi-Agent AI for Astrophysical Research

The Role Of Minerals In Prebiotic Evolution: Implications For Identifying Worlds With The Potential For Life’s Origin

Gen-EBM: An Energy Balance Model For Terrestrial Planets. Climate Multistability From Snowball To Post-runaway Greenhouse Climates

Where Skies Meet: Multidisciplinary Views of Planet and Exoplanet Atmospheres

JAXA Martian Moons eXploration (MMX) Launch

2026 NASA Cosmic Origins Early-Career Workshop

NASA Space Apps Challenge 2026

Rocky Worlds DDT Workshop