Key Facts


18882 (1999 YN4) is a mid-sized asteroid whose orbit approaches the orbit of Earth but does not cross it. NASA JPL has classified 1999 YN4 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.

1999 YN4 orbits the sun every 799 days (2.19 years), coming as close as 1.29 AU and reaching as far as 2.08 AU from the sun. Based on its brightness and the way it reflects light, 1999 YN4 is probably between 1.693 to 3.785 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to Mount Everest.

1999 YN4's spectral type None (Tholen) / S (SMASSII) indicates that it is likely to contain and .

No Close Approaches

1999 YN4's orbit is 0.43 AU from Earth's orbit at its closest point. This means that there is an 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 YN4's orbit is determined by observations dating back to Jan. 4, 1954. It was last officially observed on July 2, 2021. The IAU Minor Planet Center records 907 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 YN4:



   or view a random object

Orbital Elements

  • Epoch: 2459396.5 JD
  • Semi-major axis: 1.685 AU
  • Eccentricity: 0.2321
  • Inclination: 36.81°
  • Longitude of Ascending Node: 291.69°
  • Argument of Periapsis: 242.68°
  • Mean Anomaly: 227.38°

Physical Characteristics

  • Diameter: ~2.185 km
  • Magnitude: 15.98
  • Spectral type (SMASS): S

Derived Characteristics

  • Orbit Period: 799 days (2.19 years)
  • Avg. Orbit Speed: 22.94 km/s
  • Aphelion Distance: 2.08 AU
  • Perihelion Distance: 1.29 AU
  • Approx. Composition: and .

Map Comparison

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Orbit Simulation

Sky Map

The position of 18882 (1999 YN4) 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 1999 YN4 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.