Southwest Research Institute, Boulder, CO 80302, USA.
NASA Ames Research Center, Moffett Field, CA 94035-1000, USA.
Science. 2020 Feb 28;367(6481). doi: 10.1126/science.aay3999. Epub 2020 Feb 13.
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. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
冷经典柯伊伯带是一类位于海王星之外、轨道未受干扰的小天体，由原始物体组成，这些物体保存了有关太阳系形成的信息。2019 年 1 月，新视野号飞船飞越了其中一个物体，这是一个 36 公里长的接触双星（486958）Arrokoth（暂定名称 2014 MU）。飞越的图像显示，Arrokoth 没有可检测到的光环，在 8000 公里半径范围内没有卫星（直径大于 180 米）。Arrokoth 表面有轻微的陨石坑，光滑，具有复杂的地质特征，与之前访问过的太阳系天体不同。撞击陨石坑的密度表明表面形成于太阳系形成时期。接触双星的两个叶瓣具有紧密对齐的极和赤道，约束了它们的吸积机制。
