Key Facts


Comet P/2017 Y3 (Leonard) is an object with a medium-length orbit that is highly inclined to the ecliptic plane of the solar system. NASA JPL has classified Leonard as a "Near Earth Asteroid" due to its orbit's proximity to Earth, but it is not considered potentially hazardous because computer simulations have not indicated any imminent likelihood of future collision.

Leonard orbits the sun every 11,300 days (30.94 years), coming as close as 1.28 AU and reaching as far as 18.45 AU from the sun. Its orbit is highly elliptical.

No Close Approaches

Leonard's orbit is 0.49 AU from Earth's orbit at its closest point. This means that there is an 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

Leonard's orbit is determined by observations dating back to Dec. 26, 2017. It was last officially observed on Sept. 17, 2018. The IAU Minor Planet Center records 93 observations used to determine its orbit.

Accessibility and Exploration

This comet 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 Leonard:



   or view a random object

Orbital Elements

  • Epoch: 2458169.5 JD
  • Semi-major axis: 9.865 AU
  • Eccentricity: 0.8707
  • Inclination: 27.59°
  • Longitude of Ascending Node: 153.87°
  • Argument of Periapsis: 67.53°
  • Mean Anomaly: 0.28°

Physical Characteristics

  • Magnitude: 16.5

Derived Characteristics

  • Orbit Period: 11,300 days (30.94 years)
  • Avg. Orbit Speed: 9.50 km/s
  • Aphelion Distance: 18.45 AU
  • Perihelion Distance: 1.28 AU

Orbit Simulation

Sky Map

The position of P/2017 Y3 (Leonard) 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.