期刊
EARTH AND PLANETARY SCIENCE LETTERS
卷 520, 期 -, 页码 26-33出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.epsl.2019.05.027
关键词
Mercury; ice; polar deposits; ages; Moon
资金
- NASA [NNX16AT19H]
- Solar System Exploration Research Virtual Institute [NNA14AB01A]
- NASA Discovery Program
- Goddard Space Flight Center Internal Science Funding Model
Surface ice at the poles of Mercury appears as several-m-thick deposits that are composed of nearly pure water. We provide new age estimates of the surfaces of Mercury's polar deposits from combined analyses of Poisson statistics and direct observations of crater densities within permanently shadowed, radar-bright regions imaged by the MESSENGER spacecraft. These age estimates conservatively suggest that ice was delivered to Mercury within the last similar to 330 Myr. The geologically young ages suggest that the surfaces have been recently refreshed, and this may be accomplished by the delivery of ice in a young impactor or impactors. A single, recent impactor is more consistent with the relative purity of the ice, as suggested by the Earth-based radar observations. In contrast to ice on Mercury, observations of the lunar poles are suggestive of a highly patchy distribution of surface frost. The patchiness of lunar polar deposits is consistent with long exposure times to the space weathering environment. Given enough time, the polar deposits on Mercury may age into a more heterogeneous spatial distribution, similar to that on the Moon. (C) 2019 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据