Key Facts


Pholus is a large asteroid with an orbit between Jupiter and Neptune. NASA JPL has not classified Pholus as potentially hazardous because its orbit does not bring it close to Earth.

Pholus orbits the sun every 33,400 days (91.44 years), coming as close as 8.67 AU and reaching as far as 31.91 AU from the sun. Pholus is about 190.0 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Maryland.

The rotation of Pholus has been observed. It completes a rotation on its axis every 9.98 hours.

No Close Approaches

Pholus's orbit is 7.68 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

Pholus's orbit is determined by observations dating back to July 22, 1977. It was last officially observed on April 19, 2018. The IAU Minor Planet Center records 392 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 Pholus:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 20.29 AU
  • Eccentricity: 0.5728
  • Inclination: 24.69°
  • Longitude of Ascending Node: 119.36°
  • Argument of Periapsis: 354.61°
  • Mean Anomaly: 126.19°

Physical Characteristics

  • Diameter: 190.00000 km
  • Magnitude: 7.07
  • Albedo: 0.044
  • Spectral type (Tholen): Z

Derived Characteristics

  • Orbit Period: 33,400 days (91.44 years)
  • Avg. Orbit Speed: 6.61 km/s
  • Aphelion Distance: 31.91 AU
  • Perihelion Distance: 8.67 AU
  • Rotation Period: 9.98 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of Pholus 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.