Key Facts


Iris is a large asteroid orbiting between Mars and Jupiter in the main portion of the asteroid belt. NASA JPL has not classified Iris as potentially hazardous because its orbit does not bring it close to Earth.

Iris orbits the sun every 1,350 days (3.70 years), coming as close as 1.84 AU and reaching as far as 2.94 AU from the sun. Iris is about 199.8 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Maryland.

The rotation of Iris has been observed. It completes a rotation on its axis every 7.14 hours.

Iris's spectral type S (Tholen) / S (SMASSII) indicates that it is likely to contain and .

No Close Approaches

Iris's orbit is 0.85 AU from Earth's orbit at its closest point. This means that there is a very 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

Iris's orbit is determined by observations dating back to Aug. 23, 1848. It was last officially observed on May 22, 2022. The IAU Minor Planet Center records 5,328 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 Iris:



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Orbital Elements

  • Epoch: 2460000.5 JD
  • Semi-major axis: 2.387 AU
  • Eccentricity: 0.2297
  • Inclination: 5.52°
  • Longitude of Ascending Node: 259.5°
  • Argument of Periapsis: 145.41°
  • Mean Anomaly: 154.48°

Physical Characteristics

  • Diameter: 199.83000 km
  • Magnitude: 5.62
  • Albedo: 0.2766
  • Spectral type (Tholen): S
  • Spectral type (SMASS): S

Derived Characteristics

  • Orbit Period: 1,350 days (3.70 years)
  • Avg. Orbit Speed: 19.24 km/s
  • Aphelion Distance: 2.94 AU
  • Perihelion Distance: 1.84 AU
  • Rotation Period: 7.14 hours
  • Approx. Composition: and .

Map Comparison

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Orbit Simulation

Sky Map

The position of Iris 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.