Space Weathering Effects in Troilite by Simulated Solar-Wind Hydrogen and Helium Ion Irradiation.

Autor: Christoph JM; School of Earth and Space Exploration Arizona State University Tempe AZ USA., Minesinger GM; Laboratory of Astrophysics and Surface Physics University of Virginia Charlottesville VA USA., Bu C; Laboratory of Astrophysics and Surface Physics University of Virginia Charlottesville VA USA.; Columbia Astrophysics Laboratory Columbia University New York NY USA., Dukes CA; Laboratory of Astrophysics and Surface Physics University of Virginia Charlottesville VA USA., Elkins-Tanton LT; School of Earth and Space Exploration Arizona State University Tempe AZ USA.
Jazyk: angličtina
Zdroj: Journal of geophysical research. Planets [J Geophys Res Planets] 2022 May; Vol. 127 (5), pp. e2021JE006916. Date of Electronic Publication: 2022 May 17.
DOI: 10.1029/2021JE006916
Abstrakt: Space weathering is a key process in the interpretation of airless planetary surfaces. As we engage new missions to planetary objects with potentially novel surfaces such as 16 Psyche, there is renewed interest in expanding our knowledge of space weathering effects to a wider variety of analog materials, including the physical/chemical effects of solar-wind ions on planetary regoliths. We have experimentally simulated the effects of solar ions on two polished thick sections of meteoritic troilite (FeS) via irradiation with 1 keV hydrogen (H + ) and 4 keV helium (He + ), to investigate effects resulting from different ion species. We detected depletion of sulfur over the course of each irradiation using in situ X-ray photoelectron spectroscopy. Sulfur depletion rates were surprisingly similar for H + and He + , interpreted as a function of subsurface ion-activated diffusion. By comparing XPS-derived elemental abundances with SDTrimSP computer simulations, we further quantified sulfur diffusion, sputtering yield, and altered-layer composition with respect to incident-ion fluence, and accounted for the influence of surface oxidation due to atmospheric sample storage. Using scanning electron microscopy, we detected an increase in nanoscale surface roughness resulting from the irradiation, which we quantified using atomic force microscopy. Based on these results, we estimate that an exposure time of order 10 3 Earth-years is required for troilite on Psyche to reach equilibrium sulfur depletion within the first atomic layer.
(© 2022 The Authors.)
Databáze: MEDLINE
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