Key Facts


Selene is a large asteroid that orbits between Mars and Jupiter in the outer reaches of the main asteroid belt. NASA JPL has not classified Selene as potentially hazardous because its orbit does not bring it close to Earth.

Selene orbits the sun every 2,120 days (5.80 years), coming as close as 2.95 AU and reaching as far as 3.51 AU from the sun. Selene is about 48.2 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Rhode Island.

The rotation of Selene has been observed. It completes a rotation on its axis every 9.47 hours.

No Close Approaches

Selene's orbit is 1.96 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

Selene's orbit is determined by observations dating back to Dec. 17, 1905. It was last officially observed on June 1, 2022. The IAU Minor Planet Center records 3,751 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 Selene:



   or view a random object

Orbital Elements

  • Epoch: 2459800.5 JD
  • Semi-major axis: 3.229 AU
  • Eccentricity: 0.0875
  • Inclination: 3.67°
  • Longitude of Ascending Node: 98.91°
  • Argument of Periapsis: 338.72°
  • Mean Anomaly: 54.5°

Physical Characteristics

  • Diameter: 48.20400 km
  • Magnitude: 10.33
  • Albedo: 0.082

Derived Characteristics

  • Orbit Period: 2,120 days (5.80 years)
  • Avg. Orbit Speed: 16.57 km/s
  • Aphelion Distance: 3.51 AU
  • Perihelion Distance: 2.95 AU
  • Rotation Period: 9.47 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of Selene 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.