Comparison of space weathering spectral changes induced by solar wind and micrometeoroid impacts using ion- and femtosecond-laser-irradiated olivine and pyroxene

0547164 - GLÚ 2022 RIV FR eng J - Journal Article
Chrbolková, Kateřina - Brunetto, R. - Ďurech, J. - Kohout, Tomáš - Mizohata, K. - Malý, P. - Dědič, V. - Lantz, C. - Penttilä, A. - Trojánek, F. - Maturilli, A.
Comparison of space weathering spectral changes induced by solar wind and micrometeoroid impacts using ion- and femtosecond-laser-irradiated olivine and pyroxene.
Astronomy & Astrophysics. Roč. 654, October 2021 (2021), č. článku A143. ISSN 0004-6361. E-ISSN 1432-0746
Institutional support: RVO:67985831
Keywords : planets and satellites: surfaces * solar wind * meteorites, meteors, meteoroids * methods: data analysis * techniques: spectroscopic
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.240, year: 2021
Method of publishing: Open access
https://www.aanda.org/articles/aa/full_html/2021/10/aa40372-21/aa40372-21.html

Context. Space weathering is a process that changes the surface of airless planetary bodies. Prime space weathering agents are solar wind irradiation and micrometeoroid bombardment. These processes alter planetary reflectance spectra and often modify their compositional diagnostic features.
Aims. In this work we focused on simulating and comparing the spectral changes caused by solar wind irradiation and by micrometeoroid bombardment to gain a better understanding of these individual space weathering processes.
Methods. We used olivine and pyroxene pellets as proxies for planetary materials. To simulate solar wind irradiation we used hydrogen, helium, and argon ions with energies from 5 to 40 keV and fluences of up to 10¹⁸ particles cm⁻². To simulate micrometeoroid bombardment we used individual femtosecond laser pulses. We analysed the corresponding evolution of different spectral parameters, which we determined by applying the Modified Gaussian Model, and we also conducted principal component analysis.
Results. The original mineralogy of the surface influences the spectral evolution more than the weathering agent, as seen from the diverse evolution of the spectral slope of olivine and pyroxene upon irradiation. The spectral slope changes seen in olivine are consistent with observations of A-type asteroids, while the moderate to no slope changes observed in pyroxene are consistent with asteroid (4) Vesta. We also observed some differences in the spectral effects induced by the two weathering agents. Ions simulating solar wind have a smaller influence on longer wavelengths of the spectra than laser irradiation simulating micrometeoroid impacts. This is most likely due to the different penetration depths of ions and laser pulses. Our results suggest that in some instances it might be possible to distinguish between the contributions of the two agents on a weathered surface.
Permanent Link: http://hdl.handle.net/11104/0323487