Key Facts


Eunomia is a very large asteroid orbiting between Mars and Jupiter in the main portion of the asteroid belt. NASA JPL has not classified Eunomia as potentially hazardous because its orbit does not bring it close to Earth.

Eunomia orbits the sun every 1,570 days (4.30 years), coming as close as 2.15 AU and reaching as far as 3.14 AU from the sun. Eunomia is about 231.7 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Maryland.

The rotation of Eunomia has been observed. It completes a rotation on its axis every 6.08 hours.

Eunomia's spectral type S (Tholen) / S (SMASSII) indicates that it is likely to contain and .

No Close Approaches

Eunomia's orbit is 1.19 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

Eunomia's orbit is determined by observations dating back to Sept. 2, 1851. It was last officially observed on June 2, 2023. The IAU Minor Planet Center records 4,747 observations used to determine its orbit.

Scientists have been able to determine this object's shape:

View asteroid Eunomia in 3D.

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 Eunomia:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 2.643 AU
  • Eccentricity: 0.1871
  • Inclination: 11.75°
  • Longitude of Ascending Node: 292.91°
  • Argument of Periapsis: 98.76°
  • Mean Anomaly: 289.99°

Physical Characteristics

  • Diameter: 231.68900 km
  • Magnitude: 5.41
  • Albedo: 0.248
  • Spectral type (Tholen): S
  • Spectral type (SMASS): S

Derived Characteristics

  • Orbit Period: 1,570 days (4.30 years)
  • Avg. Orbit Speed: 18.31 km/s
  • Aphelion Distance: 3.14 AU
  • Perihelion Distance: 2.15 AU
  • Rotation Period: 6.08 hours
  • Approx. Composition: and .

Map Comparison

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Orbit Simulation

Sky Map

The position of Eunomia 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.