Key Facts

  • Categorized as a Jupiter Trojan
  • Comparable in size to the U.S. state of Delaware (117.79 km diameter)
  • Not a Near Earth Object
  • Not a Potentially Hazardous Object
  • See orbit simulation


Diomedes is a large asteroid that shares Jupiter's orbit around the sun. NASA JPL has not classified Diomedes as potentially hazardous because its orbit does not bring it close to Earth.

Diomedes orbits the sun every 4,350 days (11.91 years), coming as close as 4.98 AU and reaching as far as 5.46 AU from the sun. Diomedes is about 117.8 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Delaware.

The rotation of Diomedes has been observed. It completes a rotation on its axis every 24.49 hours.

No Close Approaches

Diomedes's orbit is 4.03 AU from Earth's orbit at its closest point. This means that there is an extremely wide berth between this asteroid and Earth at all times.

Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.

Images and Observations

Diomedes's orbit is determined by observations dating back to Aug. 3, 1937. It was last officially observed on May 15, 2023. The IAU Minor Planet Center records 4,147 observations used to determine its orbit.

Accessibility and Exploration

This asteroid is not considered a viable target for human exploration by the NHATS study.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of Diomedes:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 5.219 AU
  • Eccentricity: 0.0461
  • Inclination: 20.47°
  • Longitude of Ascending Node: 315.79°
  • Argument of Periapsis: 129.32°
  • Mean Anomaly: 41.98°

Physical Characteristics

  • Diameter: 117.78600 km
  • Magnitude: 8.24
  • Albedo: 0.061
  • Spectral type (Tholen): DP

Derived Characteristics

  • Orbit Period: 4,350 days (11.91 years)
  • Avg. Orbit Speed: 13.05 km/s
  • Aphelion Distance: 5.46 AU
  • Perihelion Distance: 4.98 AU
  • Rotation Period: 24.49 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of Diomedes is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.