Southwest Research Institute, Boulder, CO 80302, USA.
Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
Science. 2019 May 17;364(6441). doi: 10.1126/science.aaw9771.
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. We describe initial results from these encounter observations. MU is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.
柯伊伯带是太阳系外的一个遥远区域。2019 年 1 月 1 日，新视野号飞船近距离飞越（486958）2014 MU，这是一个直径约 30 公里的冰冷经典柯伊伯带物体。由于从未受到太阳的强烈加热，这些物体自形成以来保存完好。我们描述了这些遭遇观测的初步结果。MU 是一个双叶接触双星，具有扁平形状、离散的地质单元和明显的反照率非均质性。然而，表面颜色或成分非均质性很小。没有发现卫星、光环或其他尘埃结构、气体彗发或太阳风相互作用的证据。MU 的起源似乎与鹅卵石云的崩塌一致，随后是其两个叶瓣的低速合并。
