Key Facts

Overview

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

Hirokun orbits the sun every 1,510 days (4.13 years), coming as close as 2.42 AU and reaching as far as 2.72 AU from the sun. Based on its brightness and the way it reflects light, Hirokun is probably between 7.881 to 17.621 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to the city of Boston.

The rotation of Hirokun has been observed. It completes a rotation on its axis every 6.96 hours.

No Close Approaches

Hirokun's orbit is 1.42 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

Hirokun's orbit is determined by observations dating back to Feb. 11, 1991. It was last officially observed on April 12, 2023. The IAU Minor Planet Center records 3,439 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 Hirokun:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 2.572 AU
  • Eccentricity: 0.0579
  • Inclination: 13.99°
  • Longitude of Ascending Node: 271.06°
  • Argument of Periapsis: 316.95°
  • Mean Anomaly: 263.15°

Physical Characteristics

  • Diameter: ~10.174 km
  • Magnitude: 12.64

Derived Characteristics

  • Orbit Period: 1,510 days (4.13 years)
  • Avg. Orbit Speed: 18.53 km/s
  • Aphelion Distance: 2.72 AU
  • Perihelion Distance: 2.42 AU
  • Rotation Period: 6.96 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of Hirokun 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.