Themis

24 Themis (A853 GA)

Space Reference » Main-belt Asteroids » Themis

Key Facts

Overview

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

Themis orbits the sun every 2,040 days (5.59 years), coming as close as 2.78 AU and reaching as far as 3.52 AU from the sun. Themis is about 198.0 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Maryland.

The rotation of Themis has been observed. It completes a rotation on its axis every 8.37 hours.

Themis's spectral type C (Tholen) / B (SMASSII) indicates that it is likely to contain hydrogen, nitrogen, ammonia, and iron.

No Close Approaches

Themis's orbit is 1.79 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

Themis's orbit is determined by observations dating back to April 27, 1853. It was last officially observed on Feb. 2, 2023. The IAU Minor Planet Center records 4,857 observations used to determine its orbit.

Scientists have been able to determine this object's shape:

View asteroid Themis in 3D.

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 Themis:

References

Search

   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 3.149 AU
  • Eccentricity: 0.1165
  • Inclination: 0.74°
  • Longitude of Ascending Node: 36.5°
  • Argument of Periapsis: 108.06°
  • Mean Anomaly: 276.3°

Physical Characteristics

  • Diameter: 198.00000 km
  • Magnitude: 7.27
  • Albedo: 0.067
  • Spectral type (Tholen): C
  • Spectral type (SMASS): B

Derived Characteristics

  • Orbit Period: 2,040 days (5.59 years)
  • Avg. Orbit Speed: 16.79 km/s
  • Aphelion Distance: 3.52 AU
  • Perihelion Distance: 2.78 AU
  • Rotation Period: 8.37 hours
  • Approx. Composition: hydrogen, nitrogen, ammonia, and iron.

Map Comparison

Click to load map

Orbit Simulation

⧉

Sky Map

The position of Themis 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.