Key Facts


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

Hygiea orbits the sun every 2,030 days (5.56 years), coming as close as 2.79 AU and reaching as far as 3.49 AU from the sun. Hygiea is about 407.1 kilometers in diameter, making it one of the largest objects, comparable in size to the U.S. state of Iowa.

The rotation of Hygiea has been observed. It completes a rotation on its axis every 13.83 hours.

Hygiea's spectral type C (Tholen) / C (SMASSII) indicates that it is likely to contain water, iron, nickel, cobalt, nitrogen, and ammonia.

No Close Approaches

Hygiea's orbit is 1.78 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

Hygiea's orbit is determined by observations dating back to May 26, 1849. It was last officially observed on June 23, 2023. The IAU Minor Planet Center records 4,463 observations used to determine its orbit.

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

View asteroid Hygiea 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 Hygiea:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 3.14 AU
  • Eccentricity: 0.111
  • Inclination: 3.83°
  • Longitude of Ascending Node: 283.17°
  • Argument of Periapsis: 312.48°
  • Mean Anomaly: 75.18°

Physical Characteristics

  • Diameter: 407.12000 km
  • Magnitude: 5.64
  • Albedo: 0.0717
  • Spectral type (Tholen): C
  • Spectral type (SMASS): C

Derived Characteristics

  • Orbit Period: 2,030 days (5.56 years)
  • Avg. Orbit Speed: 16.83 km/s
  • Aphelion Distance: 3.49 AU
  • Perihelion Distance: 2.79 AU
  • Rotation Period: 13.83 hours
  • Approx. Composition: water, iron, nickel, cobalt, nitrogen, and ammonia.

Map Comparison

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Orbit Simulation

Sky Map

The position of Hygiea 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.