Moons · Space Codex
Oberon
Uranus's second-largest moon, an old cratered world of roughly half ice and half rock, with at least one mountain about 6 km high.
The outermost major moon of Uranus
At a glance
Key points
- Uranus's second-largest moon
- A mountain about 6 km high
- Named after the fairy king in A Midsummer Night's Dream
Surface
Oberon is heavily cratered, and some crater floors carry dark material, possibly erupted from below. Its orbit sometimes takes it outside Uranus's magnetosphere, where the solar wind strikes the surface directly.
Exploration
Voyager 2 is the only spacecraft to have visited, passing on 24 January 1986. Uranus was near solstice, so only the southern hemispheres of its moons were in sunlight; the northern halves have never been seen up close.
What we still don't know
What the dark crater-floor deposits are, and whether Oberon's interior is layered.
Missions
- 1977–
The only spacecraft to visit Uranus (1986) and Neptune (1989); interstellar since 5 Nov 2018.
First-hand · our 3D model
How we render it
Oberon is a sphere wrapped in a global map built from USGS and NASA spacecraft mosaics. Voyager 2 imaged only one hemisphere, so the unseen side is a feathered procedural fill.
It is drawn at about 8.8% of Uranus's radius, enlarged from its true 3.0% so it stays visible. It orbits in Uranus's equatorial frame, inclined 0.1°, with a 13.46-day period kept in true ratio to its neighbours, and keeps one face towards Uranus.
Moon sizes and orbits are compressed so a whole system fits on screen, but never reordered: each moon is drawn at 0.72 × (true size ratio)^0.6 of its planet, capped so no large moon is drawn bigger than it really is, and orbit distances are log-compressed into a band that clears the planet's rings. Orbital periods keep their true ratios, every moon is tidally locked, and on lighter devices only the two largest moons of each planet are drawn.
Related entries
Sources
- JPL Solar System Dynamics: satellite physical parameters (opens in a new tab)
- JPL Solar System Dynamics: satellite mean orbital elements (opens in a new tab)
- NASA NSSDC Uranian Satellite Fact Sheet (opens in a new tab)
- NASA Science: Oberon (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.