DOI: 10.1038/ngeo2397
论文题名: Darkening of Mercury's surface by cometary carbon
作者: Syal M.B. ; Schultz P.H. ; Riner M.A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2015
卷: 8, 期: 5 起始页码: 352
结束页码: 356
语种: 英语
Scopus关键词: carbon
; fractionation
; iron
; Mercury (planet)
; Moon
; numerical model
; planetary surface
; reflectance
; spectroscopy
英文摘要: Mercury's surface is darker than that of the Moon. Iron-bearing minerals and submicroscopic metallic iron produced by space weathering are the primary known darkening materials on airless bodies. Yet Mercury's iron abundance at the surface is lower than the Moon's; another material is therefore likely to be responsible for Mercury's dark surface. Enhanced darkening by submicroscopic metallic iron particles under intense space weathering at Mercury's surface is insufficient to reconcile the planet's low reflectance with its low iron abundance. Here we show that the delivery of cometary carbon by micrometeorites provides a mechanism to darken Mercury's surface without violating observational constraints on iron content. We calculate the micrometeorite flux at Mercury and numerically simulate the fraction of carbonaceous material retained by the planet following micrometeorite impacts. We estimate that 50 times as many carbon-rich micrometeorites per unit surface area are delivered to Mercury, compared with the Moon, resulting in approximately 3-6 wt% carbon at Mercury's surface (in graphite, amorphous, or nanodiamond form). Spectroscopic analysis of products of hypervelocity impact experiments demonstrates that the incorporation of carbon effectively darkens and weakens spectral features, consistent with remote observations of Mercury. Carbon delivery by micrometeorites provides an explanation for Mercury's globally low reflectance and may contribute to the darkening of planetary surfaces elsewhere. © 2015 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106219
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Lawrence Livermore National Laboratory, PO Box 808 L-405, Livermore, CA, United States; Department of Earth Environmental, and Planetary Sciences, Brown University, Box 1846, 324 Brook St, Providence, RI, United States; Planetary Science Institute, 1700 East Fort Lowell, Tucson, AZ, United States
Recommended Citation:
Syal M.B.,Schultz P.H.,Riner M.A.. Darkening of Mercury's surface by cometary carbon[J]. Nature Geoscience,2015-01-01,8(5)