hydroxyl group
; mineral
; oxygen
; silicate
; water
; article
; astronomy
; dust
; electron energy loss spectroscopy
; priority journal
; radiolysis
; soil
; solar radiation
; space
; transmission electron microscopy
; weathering
英文摘要:
The solar wind (SW), composed of predominantly ∼1-keV H+ ions, produces amorphous rims up to ∼150 nm thick on the surfaces of minerals exposed in space. Silicates with amorphous rims are observed on interplanetary dust particles and on lunar and asteroid soil regolith grains. Implanted H+ may react with oxygen in the minerals to form trace amounts of hydroxyl (-OH) and/or water (H2O). Previous studies have detected hydroxyl in lunar soils, but its chemical state, physical location in the soils, and source(s) are debated. If -OH or H2O is generated in rims on silicate grains, there are important implications for the origins of water in the solar system and other astrophysical environments. By exploiting the high spatial resolution of transmission electron microscopy and valence electron energy-loss spectroscopy, we detect water sealed in vesicles within amorphous rims produced by SW irradiation of silicate mineral grains on the exterior surfaces of interplanetary dust particles. Our findings establish that water is a byproduct of SW space weathering. We conclude, on the basis of the pervasiveness of the SW and silicate materials, that the production of radiolytic SW water on airless bodies is a ubiquitous process throughout the solar system.
Bradley, J.P., Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States, Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI 96822, United States; Ishii, H.A., Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States, Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI 96822, United States; Gillis-Davis, J.J., Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI 96822, United States; Ciston, J., National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Nielsen, M.H., Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States, Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, United States; Bechtel, H.A., Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Martin, M.C., Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
Recommended Citation:
Bradley J.P.,Ishii H.A.,Gillis-Davis J.J.,et al. Detection of solar wind-produced water in irradiated rims on silicate minerals[J]. Proceedings of the National Academy of Sciences of the United States of America,2014-01-01,111(5)