Physikalisches Institut, Universität Bern, 3012 Bern, Switzerland.
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80301, USA.
Science. 2017 Mar 31;355(6332):1392-1395. doi: 10.1126/science.aak9384. Epub 2017 Mar 21.
The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet's landscape. This suggests that most of the major landforms were created early in the comet's current orbital configuration. They may even date from earlier if the comet had a larger volatile inventory, particularly of CO or CO ices, or contained amorphous ice, which could have triggered activity at greater distances from the Sun.
罗塞塔号飞船在彗星 67P/楚留莫夫-格拉希门克上空约两年的轨道运行中，大部分时间都在允许进行亚米级表面特征描述和监测的距离内。从 2014 年 12 月到 2016 年 6 月，我们观察到了许多局部变化，我们认为这些变化归因于彗星特有的风化、侵蚀和由暴露在阳光下和其他过程驱动的瞬态事件。虽然局部变化表明存在成分或物理不均匀性，但它们的规模并没有导致彗星地貌发生实质性的改变。这表明大多数主要地貌都是在彗星当前轨道构型的早期形成的。如果彗星有更多的挥发性物质，特别是 CO 或 CO 冰，或者含有非晶态冰，它们甚至可能追溯到更早的时期，因为这些物质可能会在离太阳更远的地方引发活动。
