scholarly journals Detecting Sub-Micron Space Weathering Effects in Lunar Grains with Synchrotron Infrared Nanospectroscopy

2021 ◽  
Author(s):  
Kainen L. Utt ◽  
Ryan C. Ogliore ◽  
Hans A. Bechtel ◽  
Jeffrey Gillis-Davis ◽  
Bradley L. Jolliff
Icarus ◽  
2016 ◽  
Vol 269 ◽  
pp. 1-14 ◽  
Author(s):  
S. Fornasier ◽  
C. Lantz ◽  
D. Perna ◽  
H. Campins ◽  
M.A. Barucci ◽  
...  

2020 ◽  
Author(s):  
Paul Stefan Szabo ◽  
Herbert Biber ◽  
Noah Jäggi ◽  
Matthias Brenner ◽  
David Weichselbaum ◽  
...  

<p>In the absence of a protecting atmosphere, the surfaces of rocky bodies in the solar system are affected by significant space weathering due to the exposure to the solar wind [1]. Fundamental knowledge of space weathering effects, such as optical changes of surfaces as well as the formation of an exosphere is essential for gaining insights into the history of planetary bodies in the solar system [2]. Primarily the exospheres of Mercury and Moon are presently of great interest and the interpretation of their formation processes relies on the understanding of all space weathering effects on mineral surfaces.</p><p>Sputtering of refractory elements by solar wind ions is one of the most important release processes. We investigate solar wind sputtering by measuring and modelling the sputtering of pyroxene samples as analogues for the surfaces of Mercury and Moon [3, 4]. These measurements with thin film samples on Quartz Crystal Microbalance (QCM) substrates allow recording of sputtering yields in-situ and in real time [5]. For the simulation of kinetic sputtering from the ion-induced collision cascade we use the software SDTrimSP with adapted input parameters that consistently reproduce measured kinetic sputtering yields [4, 6].</p><p>This study focuses on investigating the potential sputtering of insulating samples by multiply charged ions [7]. Changes of these sputtering yields with fluence are compared to calculations with a model based on inputs from SDTrimSP simulations. This leads to a very good agreement with steady-state sputtering yields under the assumption that only O atoms are sputtered by the potential energy of the ions. The observed decreasing sputtering yields can be explained by a partial O depletion on the surface [4]. Based on these findings expected surface composition changes and sputtering yields under realistic solar wind conditions can be calculated. Our results are in line with previous investigations (see e.g. [8, 9]), creating a consistent view on solar wind sputtering effects from experiments to established modelling efforts.</p><p> </p><p><strong>References:</strong></p><p>[1]          B. Hapke, J. Geophys. Res.: Planets, <strong>106</strong>, 10039 (2001).</p><p>[2]          P. Wurz, et al., Icarus, <strong>191</strong>, 486 (2007).</p><p>[3]          P.S. Szabo, et al., Icarus, <strong>314</strong>, 98 (2018).</p><p>[4]          P.S. Szabo, et al., submitted to Astrophys. J. (2020).</p><p>[5]          G. Hayderer, et al., Rev. Sci. Instrum., <strong>70</strong>, 3696 (1999).</p><p>[6]          A. Mutzke, et al., “SDTrimSP Version 6.00“, IPP Report, (2019).</p><p>[7]          F. Aumayr, H. Winter, Philos. Trans. R. Soc. A, <strong>362</strong>, 77 (2004).</p><p>[8]          H. Hijazi, et al., J. Geophys. Res.: Planets, <strong>122</strong>, 1597 (2017).</p><p>[9]          S.T. Alnussirat, et al., Nucl. Instrum. Methods Phys. Res. B, <strong>420</strong>, 33 (2018).</p>


2021 ◽  
Author(s):  
Antti Penttilä ◽  
Timo Väisänen ◽  
Johannes Markkanen ◽  
Julia Martikainen ◽  
Tomas Kohout ◽  
...  

<p>We present a multi-scale light-scattering model that is capable of simulating the reflectance spectra of a regolith layer. In particular, the model can be applied to a case where the regolith grains have varying amounts of nanophase inclusions due to space weathering of the material. As different simulation tools are employed for different size scales of the target geometry (roughly, nano-, micro-, and millimeter scales), the particle size effects, the surface reflections, and the volume scattering can all be properly accounted for. Our results with olivine grains and nanophase iron inclusions verify the role of the nanoinclusions in the reflectance spectra of space-weathered materials. Together with the simulation results, we give simplified explanations for the space-weathering effects based on light scattering, namely the decrease of albedo, the general increase of the red spectral slope, and the dampening of the spectral bands. We also consider the so-called ultraviolet bluing effect and show how the change in the spectral slope over the ultraviolet-visual wavelengths is due to the decrease of reflectance in the visual wavelengths rather than the increase of reflectance in the ultraviolet part.</p>


Icarus ◽  
2020 ◽  
Vol 345 ◽  
pp. 113727 ◽  
Author(s):  
Antti Penttilä ◽  
Timo Väisänen ◽  
Johannes Markkanen ◽  
Julia Martikainen ◽  
Tomáš Kohout ◽  
...  

2020 ◽  
Vol 26 (S2) ◽  
pp. 2598-2601
Author(s):  
Dara Laczniak ◽  
Michelle Thompson ◽  
Catherine Dukes ◽  
Richard Morris ◽  
Simon Clemett ◽  
...  

Icarus ◽  
2017 ◽  
Vol 283 ◽  
pp. 343-351 ◽  
Author(s):  
Paul G. Lucey ◽  
Benjamin T. Greenhagen ◽  
Eugenie Song ◽  
Jessica A. Arnold ◽  
Myriam Lemelin ◽  
...  

A new microprobing procedure is used to characterize both the physical and chemical surface properties of individual grains on a microscale. In this procedure the same sub-micrometre sized area of a given grain is successively analysed with a high voltage electron microscope, an Auger microprobe and a field emission scanning electron microscope. This analytical technique has been applied to study lunar weathering effects and to tentatively infer the irradiation history of a Nerich fraction of the Orgueil meteorite.


Sign in / Sign up

Export Citation Format

Share Document