Key Facts

Overview

528381 (2008 ST291) is a dwarf planet whose orbit extends beyond the orbit of Neptune. NASA JPL has not classified 2008 ST291 as potentially hazardous because its orbit does not bring it close to Earth.

2008 ST291 orbits the sun every 371,000 days (1,015.74 years), coming as close as 42.74 AU and reaching as far as 159.26 AU from the sun. Based on its brightness and the way it reflects light, 2008 ST291 is probably between 368.600 to 824.214 kilometers in diameter, making it one of the largest objects, very roughly comparable in size to Great Britain.

No Close Approaches

2008 ST291's orbit is 41.80 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

2008 ST291's orbit is determined by observations dating back to Sept. 24, 2008. It was last officially observed on Sept. 24, 2022. The IAU Minor Planet Center records 103 observations used to determine its orbit.

Accessibility and Exploration

This asteroid is not considered a viable target for human exploration by the NHATS study.

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 101.0 AU
  • Eccentricity: 0.5768
  • Inclination: 20.75°
  • Longitude of Ascending Node: 330.95°
  • Argument of Periapsis: 325.82°
  • Mean Anomaly: 24.35°

Physical Characteristics

  • Diameter: ~475.860 km
  • Magnitude: 4.29

Derived Characteristics

  • Orbit Period: 371,000 days (1,015.74 years)
  • Avg. Orbit Speed: 2.96 km/s
  • Aphelion Distance: 159.26 AU
  • Perihelion Distance: 42.74 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of 528381 (2008 ST291) 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.