Key Facts

  • Classified as a Jupiter Trojan
  • Comparable in size to the U.S. state of Delaware (83.99 km diameter)
  • Not a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Asteroid (PHA)
  • See orbit simulation

Overview

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

Ajax orbits the sun every 4,455 days (12.20 years), coming as close as 4.69 AU and reaching as far as 5.91 AU from the sun. Ajax is about 84.0 kilometers in diameter, making it larger than most asteroids, comparable in size to the U.S. state of Delaware.

The rotation of Ajax has been observed. It completes a rotation on its axis every 29.38 days.

No Close Approaches

Ajax's orbit is 3.74 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

Ajax's orbit is determined by observations dating back to Aug. 17, 1936. It was last officially observed on May 8, 2019. The IAU Minor Planet Center records 1,216 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 Ajax:

References

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Orbital Elements

  • Epoch: 2458600.5 JD
  • Semi-major axis: 5.29902779042 AU
  • Eccentricity: 0.114373240332
  • Inclination: 18.0140174923°
  • Longitude of Ascending Node: 332.890539945°
  • Argument of Periapsis: 60.0299519192°
  • Mean Anomaly: 279.308023678°

Physical Characteristics

  • Diameter: 83.99000 km
  • Magnitude: 9.3
  • Albedo: 0.048

Derived Characteristics

  • Orbit Period: 4,455 days (12.20 years)
  • Avg. Orbit Speed: 12.94 km/s
  • Aphelion Distance: 5.91 AU
  • Perihelion Distance: 4.69 AU
  • Rotation Period: 29.38 days

Size Comparison

Orbit Simulation

Sky Map

The position of Ajax 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.