Key Facts

Overview

26375 (1999 DE9) is a dwarf planet whose orbit extends beyond the orbit of Neptune. NASA JPL has not classified 1999 DE9 as potentially hazardous because its orbit does not bring it close to Earth.

1999 DE9 orbits the sun every 149,000 days (407.94 years), coming as close as 32.13 AU and reaching as far as 77.89 AU from the sun. Based on its brightness and the way it reflects light, 1999 DE9 is probably between 275.775 to 616.652 kilometers in diameter, making it one of the largest objects, very roughly comparable in size to the U.S. state of Mississippi.

The rotation of 1999 DE9 has been observed. It completes a rotation on its axis every 24.00 hours.

No Close Approaches

1999 DE9's orbit is 31.10 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

1999 DE9's orbit is determined by observations dating back to Jan. 29, 1990. It was last officially observed on May 24, 2023. The IAU Minor Planet Center records 503 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 1999 DE9:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 55.01 AU
  • Eccentricity: 0.4159
  • Inclination: 7.63°
  • Longitude of Ascending Node: 323.03°
  • Argument of Periapsis: 158.66°
  • Mean Anomaly: 33.39°

Physical Characteristics

  • Diameter: ~356.024 km
  • Magnitude: 4.92

Derived Characteristics

  • Orbit Period: 149,000 days (407.94 years)
  • Avg. Orbit Speed: 4.02 km/s
  • Aphelion Distance: 77.89 AU
  • Perihelion Distance: 32.13 AU
  • Rotation Period: 24.00 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of 26375 (1999 DE9) 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.