486958 Arrokoth

classical trans-Neptunian object

486958 Arrokoth,[a] provisional designation 2014 MU69, is a trans-Neptunian object located in the Kuiper belt. It is a contact binary 36 km (22 mi) long, made of two planetesimals 21 km (13 mi) and 15 km (9 mi) across, nicknamed "Ultima" and "Thule". The New Horizons team use this classical pronunciation, the pseudo-Latin pronunciation /ˈtl/ TOO-lay, and the hybrid pronunciation /ˈtl/ TOO-lee.[1][2] The surface is made of pale red tholins, formed due to the surface being exposed to UV light.[3]


  1. "New Horizons Press Kit" (PDF). Applied Physics Laboratory. December 2018. p. 5. Retrieved 1 January 2019.
  2. "New Horizons: First Images of Ultima Thule". YouTube. Applied Physics Laboratory. 1 January 2019.
  3. How Arrokoth Shocked NASA Scientists, retrieved 2021-07-12