Key Facts


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

Hylonome orbits the sun every 45,700 days (125.12 years), coming as close as 18.92 AU and reaching as far as 31.12 AU from the sun. Based on its brightness and the way it reflects light, Hylonome is probably between 60.891 to 136.157 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to the U.S. state of Delaware.

No Close Approaches

Hylonome's orbit is 17.90 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

Hylonome's orbit is determined by observations dating back to March 9, 1995. It was last officially observed on June 14, 2010. The IAU Minor Planet Center records 78 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 Hylonome:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 25.02 AU
  • Eccentricity: 0.2438
  • Inclination: 4.14°
  • Longitude of Ascending Node: 178.31°
  • Argument of Periapsis: 5.95°
  • Mean Anomaly: 81.91°

Physical Characteristics

  • Diameter: ~78.610 km
  • Magnitude: 8.2

Derived Characteristics

  • Orbit Period: 45,700 days (125.12 years)
  • Avg. Orbit Speed: 5.96 km/s
  • Aphelion Distance: 31.12 AU
  • Perihelion Distance: 18.92 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of Hylonome 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.