Key Facts


15504 (1999 RG33) is a large asteroid with an orbit between Jupiter and Neptune. NASA JPL has not classified 1999 RG33 as potentially hazardous because its orbit does not bring it close to Earth.

1999 RG33 orbits the sun every 10,500 days (28.75 years), coming as close as 2.12 AU and reaching as far as 16.61 AU from the sun. Its orbit is highly elliptical. Based on its brightness and the way it reflects light, 1999 RG33 is probably between 9.344 to 20.895 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to the city of Cleveland, Ohio.

No Close Approaches

1999 RG33's orbit is 1.41 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 RG33's orbit is determined by observations dating back to May 12, 1996. It was last officially observed on March 18, 2023. The IAU Minor Planet Center records 147 observations used to determine its orbit.

Accessibility and Exploration

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



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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 9.365 AU
  • Eccentricity: 0.7733
  • Inclination: 34.98°
  • Longitude of Ascending Node: 23.37°
  • Argument of Periapsis: 273.92°
  • Mean Anomaly: 314.76°

Physical Characteristics

  • Diameter: ~12.064 km
  • Magnitude: 12.27

Derived Characteristics

  • Orbit Period: 10,500 days (28.75 years)
  • Avg. Orbit Speed: 9.70 km/s
  • Aphelion Distance: 16.61 AU
  • Perihelion Distance: 2.12 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of 15504 (1999 RG33) 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.