Reference image
Object guide
Iapetus is notable for its stark two-tone coloration (dark leading hemisphere, bright trailing hemisphere) and an equatorial ridge that gives it a walnut-like shape. Iapetus is approximately 1,469 km across.
How to observe Iapetus
Iapetus is resolved as a separate world mainly through imaging or spacecraft data; visually, its relationship to saturn is the key observing context.
Scientific context
Useful scale comparisons are 0.115 Earth diameters, 0.023 g surface gravity, 0.217 Earth years per orbit. These values are rounded from the catalogue measurements shown on this page.
- Radius
- 734.5 km
- Diameter
- 1,469 km
- Mass
- 1,805,600,000,000,000,000,000 kg
- Mean density
- 1.088 g/cm³
- Surface gravity
- 0.223 m/s² (0.023 g)
- Orbital period
- 79.3215 days (0.217 years)
- Parent body
- saturn
0.115 Earth diameters0.023 g surface gravity0.217 Earth years per orbit
Source: NASA Science (checked 2026-08-09). Values are rounded catalogue measurements.
Interactive orbit model
Aug 13, 2026, 22:251×
Calculated positions / separate exploration scales