Arrokoth

Arrokoth, originally designated 2014 MU69, is a trans-Neptunian object in the Kuiper belt. It was discovered in 2014 by the Hubble Space Telescope during a search for a potential long-range target for NASA’s New Horizons mission. Arrokoth is a contact binary, comprised of two connected lobes that form a flattened, bilobed shape.

Orbit and physical characteristics: Arrokoth orbits the Sun in a cold classical Kuiper belt trajectory beyond Neptune, with a low orbital inclination and low eccentricity. The object is roughly 30 kilometers across at its longest dimension and consists of two roughly similar-sized lobes. Its surface appears relatively smooth and lightly cratered, suggesting a long, gentle accretion history. The albedo is low, and the surface exhibits a reddish hue indicative of complex organic materials exposed to space weathering.

Observations by New Horizons: On January 1, 2019, New Horizons performed a distant flyby of Arrokoth, providing the first close-up images of a Kuiper belt object and confirming it as one of the most distant objects visited by a spacecraft at that time. Data revealed a plain, feature-rich surface with few large craters, consistent with a low-velocity assembly of two bodies in the early solar system.

Name: The International Astronomical Union named the object Arrokoth in 2019, a word meaning "sky" in the Powhatan language. Before the official name, the object was widely referred to by the provisional nickname Ultima Thule. The designation 2014 MU69 remains its formal designation.