scholarly journals Spectral variability on primitive asteroids of the Themis and Beagle families: Space weathering effects or parent body heterogeneity?

Icarus ◽  
2016 ◽  
Vol 269 ◽  
pp. 1-14 ◽  
Author(s):  
S. Fornasier ◽  
C. Lantz ◽  
D. Perna ◽  
H. Campins ◽  
M.A. Barucci ◽  
...  
Keyword(s):  
Parent Body ◽  
Space Weathering ◽  
Spectral Variability ◽  
Weathering Effects

Combining Experiments and Modelling to Understand the Role of Potential Sputtering by Solar Wind Ions

2020 ◽  
Author(s):  
Paul Stefan Szabo ◽  
Herbert Biber ◽  
Noah Jäggi ◽  
Matthias Brenner ◽  
David Weichselbaum ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar System ◽  
Surface Composition ◽  
Space Weathering ◽  
Mineral Surfaces ◽  
Multiply Charged ◽  
History Of ◽  
System 2 ◽  
Sputtering Yields ◽  
Weathering Effects

<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>

Rigorous light-scattering simulations of space-weathering effects on reflectance spectra

2021 ◽  
Author(s):  
Antti Penttilä ◽  
Timo Väisänen ◽  
Johannes Markkanen ◽  
Julia Martikainen ◽  
Tomas Kohout ◽  
...  
Keyword(s):  
Light Scattering ◽  
Reflectance Spectra ◽  
Space Weathering ◽  
Spectral Slope ◽  
Simulation Tools ◽  
Multi Scale ◽  
Spectral Bands ◽  
Size Scales ◽  
Weathering Effects

<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>

scholarly journals Rigorous light-scattering simulations of nanophase iron space-weathering effects on reflectance spectra of olivine grains

Icarus ◽  
2020 ◽  
Vol 345 ◽  
pp. 113727 ◽  
Author(s):  
Antti Penttilä ◽  
Timo Väisänen ◽  
Johannes Markkanen ◽  
Julia Martikainen ◽  
Tomáš Kohout ◽  
...  
Keyword(s):  
Light Scattering ◽  
Reflectance Spectra ◽  
Space Weathering ◽  
Weathering Effects ◽  
Nanophase Iron

scholarly journals Investigating Space Weathering Effects Using Coordinated Analysis of a H+- and He+-Irradiated Carbonaceous Chondrite

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

scholarly journals Space weathering effects in Diviner Lunar Radiometer multispectral infrared measurements of the lunar Christiansen Feature: Characteristics and mitigation

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

scholarly journals Constraints on the ice composition of carbonaceous chondrites from their magnetic mineralogy

2021 ◽  
Author(s):  
Sanjana Sridhar ◽  
James Bryson ◽  
Ashley King ◽  
Richard Harrison
Keyword(s):  
Size Range ◽  
Parent Body ◽  
Carbonaceous Chondrites ◽  
Magnetic Mineralogy ◽  
Aqueous Alteration ◽  
First Order ◽  
Direct Replacement ◽  
History Of ◽  
Bulk Chemical ◽  
Weathering Effects

Carbonaceous chondrites experienced varying degrees of aqueous alteration on their parent asteroids, which influenced their mineralogies, textures, and bulk chemical and isotopic compositions. Although this alteration was a crucial event in the history of these meteorites, their various alteration pathways are not well understood. One phase that formed during this alteration was magnetite, and its morphology and abundance vary between and within chondrite groups, providing a means of investigating chondrite aqueous alteration. We measured bulk magnetic properties and first-order reversal curve (FORC) diagrams of CM, CI, CO, and ungrouped C2 chondrites to identify the morphology and size range of magnetite present in these meteorites. We identify two predominant pathways of aqueous alteration among these meteorites that can be distinguished by the resultant morphology of magnetite. In WIS 91600, Tagish Lake, and CI chondrites, magnetite forms predominantly from Fe-sulfides as framboids and stacked plaquettes. In CM and CO chondrites, <0.1 μm single-domain (SD) magnetite and 0.1–5 μm vortex (V) state magnetite formed predominantly via the direct replacement of metal and Fe-sulfides. After ruling out differences in temperature, water:rock ratios, terrestrial weathering effects, and starting mineralogy, we hypothesise that the primary factor controlling the pathway of aqueous alteration was the composition of the ice accreted into each chondrite group’s parent body. Nebula condensation sequences predict that the most feasible method of appreciably evolving ice concentrations was the condensation of ammonia, which will have formed a more alkaline hydrous fluid upon melting, leading to fundamentally different conditions that may have caused the formation of different magnetite morphologies. As such, we suggest that WIS 91600, Tagish Lake, and the CI chondrites accreted past the ammonia ice line, supporting a more distal or younger accretion of their parent asteroids.

Microprobe studies of space weathering effects in extraterrestrial dust grains

1977 ◽  
Vol 285 (1327) ◽  
pp. 433-439 ◽  
Keyword(s):  
Electron Microscope ◽  
Space Weathering ◽  
Chemical Surface ◽  
Analytical Technique ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
History Of ◽  
Individual Grains ◽  
Physical And Chemical ◽  
Weathering Effects

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.

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