Key Facts


Mors-Somnus is a large asteroid whose orbit extends beyond the orbit of Neptune. NASA JPL has not classified Mors-Somnus as potentially hazardous because its orbit does not bring it close to Earth.

Mors-Somnus orbits the sun every 90,100 days (246.68 years), coming as close as 28.83 AU and reaching as far as 49.81 AU from the sun. Based on its brightness and the way it reflects light, Mors-Somnus is probably between 114.434 to 255.882 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to the U.S. state of Connecticut.

The rotation of Mors-Somnus has been observed. It completes a rotation on its axis every 9.28 hours.

No Close Approaches

Mors-Somnus's orbit is 27.80 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

Mors-Somnus's orbit is determined by observations dating back to Oct. 14, 2007. It was last officially observed on Feb. 7, 2021. The IAU Minor Planet Center records 264 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 Mors-Somnus:



   or view a random object

Orbital Elements

  • Epoch: 2459396.5 JD
  • Semi-major axis: 39.32 AU
  • Eccentricity: 0.2667
  • Inclination: 11.27°
  • Longitude of Ascending Node: 196.65°
  • Argument of Periapsis: 204.85°
  • Mean Anomaly: 6.35°

Physical Characteristics

  • Diameter: ~147.734 km
  • Magnitude: 6.83

Derived Characteristics

  • Orbit Period: 90,100 days (246.68 years)
  • Avg. Orbit Speed: 4.75 km/s
  • Aphelion Distance: 49.81 AU
  • Perihelion Distance: 28.83 AU
  • Rotation Period: 9.28 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of Mors-Somnus 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.