Key Facts


Comet 18D/Perrine-Mrkos is an object whose orbit features a relatively short period, low inclination, and is controlled by Jupiter's gravitational effects. NASA JPL has classified 18D/Perrine-Mrkos 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.

18D/Perrine-Mrkos orbits the sun every 2,450 days (6.71 years), coming as close as 1.27 AU and reaching as far as 5.85 AU from the sun.

No Close Approaches

18D/Perrine-Mrkos's orbit is 0.29 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

18D/Perrine-Mrkos's orbit is determined by observations dating back to Nov. 29, 1961. It was last officially observed on Dec. 26, 1968. The IAU Minor Planet Center records 16 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 18D/Perrine-Mrkos:



   or view a random object

Orbital Elements

  • Epoch: 2440240.5 JD
  • Semi-major axis: 3.56 AU
  • Eccentricity: 0.6426
  • Inclination: 17.76°
  • Longitude of Ascending Node: 240.88°
  • Argument of Periapsis: 166.05°
  • Mean Anomaly: 11.51°

Physical Characteristics

  • Magnitude: 11.5

Derived Characteristics

  • Orbit Period: 2,450 days (6.71 years)
  • Avg. Orbit Speed: 15.81 km/s
  • Aphelion Distance: 5.85 AU
  • Perihelion Distance: 1.27 AU

Orbit Simulation

Sky Map

The position of 18D/Perrine-Mrkos 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.