Key Facts


16816 (1997 UF9) is a mid-sized asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 1997 UF9 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.

1997 UF9 orbits the sun every 633 days (1.73 years), coming as close as 0.57 AU and reaching as far as 2.31 AU from the sun. Based on its brightness and the way it reflects light, 1997 UF9 is probably between 1.467 to 3.281 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to Mount Everest.

The rotation of 1997 UF9 has been observed. It completes a rotation on its axis every 2.45 hours.

No Close Approaches

1997 UF9's orbit is 0.38 AU from Earth's orbit at its closest point. This means that there is a 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

1997 UF9's orbit is determined by observations dating back to Oct. 29, 1997. It was last officially observed on Dec. 3, 2021. The IAU Minor Planet Center records 1,057 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 1997 UF9:



   or view a random object

Orbital Elements

  • Epoch: 2459800.5 JD
  • Semi-major axis: 1.442 AU
  • Eccentricity: 0.6042
  • Inclination: 25.92°
  • Longitude of Ascending Node: 37.16°
  • Argument of Periapsis: 157.95°
  • Mean Anomaly: 0.48°

Physical Characteristics

  • Diameter: ~1.894 km
  • Magnitude: 16.29

Derived Characteristics

  • Orbit Period: 633 days (1.73 years)
  • Avg. Orbit Speed: 24.78 km/s
  • Aphelion Distance: 2.31 AU
  • Perihelion Distance: 0.57 AU
  • Rotation Period: 2.45 hours

Map Comparison

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Orbit Simulation

Sky Map

The position of 16816 (1997 UF9) 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.

Size Rendering

The above comparison is an artistic rendering that uses available data on the diameter of 1997 UF9 to create an approximate landscape rendering with Mount Everest in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.