Key Facts

Overview

Juno is a very large asteroid circling the sun between Mars and Jupiter, inside the main asteroid belt. NASA JPL does not treat Juno as potentially hazardous, because its orbit never carries it near Earth.

One lap around the sun takes Juno 1,590 days (4.35 years). Over that circuit it swings between 1.99 AU and 3.35 AU from the sun, travelling at an average of 18.26 km/s. At 246.6 kilometers across, Juno is bigger than 99% of known asteroids — roughly the size of the U.S. state of Maryland.

Juno has been watched long enough to time its spin: one full turn on its axis takes 7.21 hours.

Juno is classed as S on the Tholen scale, Sk on SMASSII.

No Close Approaches

At their nearest, the orbits of Juno and Earth stay 1.04 AU apart. That is a comfortable margin, and it holds at every point in the orbit.

Orbital simulations run by NASA JPL's CNEOS turn up no close approaches to Earth.

Images and Observations

The orbit of Juno is pinned down by sightings going back to Oct. 17, 1804, the most recent officially logged on Feb. 10, 2023. The IAU Minor Planet Center holds 7,460 observations behind that solution.

Accessibility and Exploration

The NHATS study does not rate Juno as a realistic destination for a crewed mission.

Similar Objects

These objects follow orbits with much the same shape and tilt as Juno:

References

Search

   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 2.669 AU
  • Eccentricity: 0.2562
  • Inclination: 12.99°
  • Longitude of Ascending Node: 169.84°
  • Argument of Periapsis: 247.74°
  • Mean Anomaly: 37.02°

Physical Characteristics

  • Diameter: 246.59600 km
  • Magnitude: 5.16
  • Albedo: 0.214
  • Spectral type (Tholen): S
  • Spectral type (SMASS): Sk

Derived Characteristics

  • Orbit Period: 1,590 days (4.35 years)
  • Avg. Orbit Speed: 18.26 km/s
  • Aphelion Distance: 3.35 AU
  • Perihelion Distance: 1.99 AU
  • Rotation Period: 7.21 hours

Map Comparison

Click to load map

Orbit Simulation

Sky Map

A ◯ pink circle marks where Juno sits. It may fall outside your current field of view — use the controls below to change the position, location and time.