Key Facts


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

Cyrene orbits the sun every 1,960 days (5.37 years), coming as close as 2.65 AU and reaching as far as 3.48 AU from the sun. Cyrene is about 72.2 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Delaware.

The rotation of Cyrene has been observed. It completes a rotation on its axis every 12.71 hours.

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

No Close Approaches

Cyrene's orbit is 1.65 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

Cyrene's orbit is determined by observations dating back to Aug. 17, 1873. It was last officially observed on July 14, 2021. The IAU Minor Planet Center records 3,805 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 Cyrene:



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Orbital Elements

  • Epoch: 2459396.5 JD
  • Semi-major axis: 3.064 AU
  • Eccentricity: 0.135
  • Inclination: 7.21°
  • Longitude of Ascending Node: 319.0°
  • Argument of Periapsis: 290.2°
  • Mean Anomaly: 285.7°

Physical Characteristics

  • Diameter: 72.17500 km
  • Magnitude: 7.91
  • Albedo: 0.279
  • Spectral type (Tholen): SR
  • Spectral type (SMASS): S

Derived Characteristics

  • Orbit Period: 1,960 days (5.37 years)
  • Avg. Orbit Speed: 17.01 km/s
  • Aphelion Distance: 3.48 AU
  • Perihelion Distance: 2.65 AU
  • Rotation Period: 12.71 hours
  • Approx. Composition: and .

Map Comparison

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Orbit Simulation

Sky Map

The position of Cyrene 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.