Iapetus
Two-toned: one hemisphere as dark as coal, the other as bright as snow.
Where it is right now
Iapetus is in Pisces, 8.95 AU away.
Computed for 2 August 2026, 17:00 UTC, and recomputed at least hourly. This page is cached, so treat the line above as accurate to the hour rather than to the second. The map shows the live position.
Position from a Kepler propagation of the published elements below, accurate to about an arcminute.
Facts
Every line carries the source it came from.
- Mean radius
- 734.3 kmSource: NASA/JPL Planetary Satellite Physical Parameters
- Orbits
- Saturn, 3,561,700 km out on averageSource: NASA/JPL Planetary Satellite Mean Elements
- Orbital period
- 79.3 daysSource: NASA/JPL Planetary Satellite Mean Elements
- Orbit shape
- eccentricity 0.0280, inclined 7.60 degrees to Saturn's Laplace planeSource: NASA/JPL Planetary Satellite Mean Elements
- Discovered
- 1671 by G.D. CassiniSource: NASA/JPL Planetary Satellite Discovery Circumstances
Physical size
- Mean radius
- 734 km
- Diameter
- 1,469 km across
Orbit
Elements are relative to Saturn.
- Average distance from Saturn
- 3.56 million km
- Closest and furthest
- 3.46 million km to 3.66 million km
- Eccentricity
- 0.0280, almost circular
- Inclination to Saturn's reference plane
- 18.37 degrees
- Orbital period
- 79.3 days
- Longitude of ascending node
- 143.21 degrees
- Argument of periapsis
- 214.99 degrees
- Mean anomaly at J2000.0
- 74.80 degrees
Family
Orbits Saturn.
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Catalog id iapetus. 3,172 objects on the map, of which 171 are hand-authored with sourced facts.