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

Area of Science:

• Planetary Science
• Astrobiology
• Solar System Formation

Background:

• Arrokoth (2014 MU69) is a primordial Kuiper Belt Object, offering insights into early Solar System conditions.
• Its largely undisturbed nature makes it a unique target for studying pristine solar system materials.

Purpose of the Study:

• To determine the surface composition of Arrokoth using data from the New Horizons spacecraft.
• To understand the formation and evolutionary processes of Arrokoth and the early Solar System.

Main Methods:

• Analysis of surface composition data collected by the New Horizons spacecraft.
• Spectroscopic and color variation analysis across Arrokoth's surface.
• Microwave thermal emission measurements of Arrokoth's night side.

Main Results:

• Methanol ice and organic materials were detected on Arrokoth's surface.
• Water ice was notably absent.
• Surface composition showed minimal regional variations, indicating a homogeneous origin.
• Mean brightness temperature of the winter night side was measured at 29 ± 5 Kelvin.

Conclusions:

• Arrokoth's composition suggests formation via hydrogenation of carbon monoxide-rich ice or energetic processing of methane on water ice grains.
• The object likely formed from a well-mixed reservoir of solids in the cold outer Solar System.
• Arrokoth represents a pristine sample of early Solar System materials.