486958 Arrokoth
Kuiper Belt Object· orbits the Sun
Arrokoth is a small, cold-classical Kuiper-belt object and the most distant body ever explored — a reddish, two-lobed contact binary flown past by New Horizons in 2019.
Open in 3D viewSee 486958 Arrokoth in the live, interactive 3D map
Key facts
Radius
9 km
Distance from Sun
44.1 AU
Orbital period
292.39 years
Eccentricity
0.03568
Rotation
15.92 hours
Science
Physical
- Mean radius
- 9 km
- Rotation period
- 15.92 hours
Orbital
- Semi-major axis
- 44.1 AU
- From catalogued orbital elements (MPC)
- Eccentricity
- 0.03568
- From catalogued orbital elements (MPC)
- Inclination
- 2.45 °
- From catalogued orbital elements (MPC)
- Orbital period
- 292.39 years
- From catalogued orbital elements (MPC)
- Perihelion
- 42.5 AU
- Computed from the orbital elements
- Aphelion
- 45.6 AU
- Computed from the orbital elements
- Mean orbital velocity
- 4.49 km/s
- Computed from the orbital elements
Discovery
- Discovered
- June 26, 2014
- Discoverer
- the Hubble Space Telescope, during a search for a New Horizons target
Composition
- Make-up
- A pristine, reddish body of primordial ices (including methanol) and organic tholins — preserved from the Solar System's formation.
Radiation & temperature
- Insolation
- 0.000515 S⊕ · 1/1,941 of the sunlight Earth receives
- Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
- Geometric albedo
- 0.21
- Geometric (V-band) albedo (New Horizons); a dark, red surface.
- Equilibrium temperature
- 40 K (-234 °C)
- Computed from albedo + distance from the Sun (airless black body); uses the geometric albedo as an estimate
- Measured mean temperature
- 40 K (-233 °C)
Discovery & history
- Discovered
- June 26, 2014
- By
- the Hubble Space Telescope, during a search for a New Horizons target
- Method
- Photographic plates
- Name
- A Powhatan/Algonquian word for 'sky'.
Arrokoth was found by Hubble in 2014 specifically as a flyby target for New Horizons after Pluto. On 1 January 2019 the spacecraft swept past it 6.6 billion km from the Sun — the most distant object ever explored up close. It proved to be a pristine contact binary: two flattened lobes gently joined into a 'snowman', a frozen relic of how planetesimals first assembled.
First close-up of a cold classical Kuiper-belt object — a pristine contact-binary 'snowman'.
Images
Images from open archives · credit shown per image