Lowell Observatory, Flagstaff, AZ 86001, USA.
Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ 86011, USA.
Science. 2020 Feb 28;367(6481). doi: 10.1126/science.aay3705. Epub 2020 Feb 13.
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. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, which suggests that Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29 ± 5 kelvin.
太阳系外物体（486958）“远野”（暂定名称 2014 MU）自形成以来基本未受干扰。我们使用新视野号航天器收集的数据研究了其表面成分。甲醇冰和有机物质都存在，有机物质可能是通过简单分子的辐照形成的。未检测到水冰。这种组成表明，富含一氧化碳的冰发生了加氢作用，或者在早期太阳系寒冷的外缘，水冰颗粒上凝结的甲烷发生了高能处理。整个表面的颜色和光谱只有很小的区域性变化，这表明“远野”是由均匀或充分混合的固体源形成的。冬季夜间侧的微波热发射与平均亮度温度 29±5 开尔文一致。
