The solar nebula origin of (486958) Arrokoth, a primordial contact binary in the Kuiper Belt.

The New Horizons spacecraft's encounter with the cold classical Kuiper Belt object (486958) Arrokoth (provisional designation 2014 MU) revealed a contact-binary planetesimal. We investigated how Arrokoth formed and found that it is the product of a gentle, low-speed merger in the early Solar System. Its two lenticular lobes suggest low-velocity accumulation of numerous smaller planetesimals within a gravitationally collapsing cloud of solid particles.

The geology and geophysics of Kuiper Belt object (486958) Arrokoth.

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers.

Color, composition, and thermal environment of Kuiper Belt object (486958) Arrokoth.

The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules.

Detection of ammonia on Pluto's surface in a region of geologically recent tectonism.

We report the detection of ammonia (NH) on Pluto's surface in spectral images obtained with the New Horizons spacecraft that show absorption bands at 1.65 and 2.2 μm.

Initial results from the New Horizons exploration of 2014 MU, a small Kuiper Belt object.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation.