Space Weathering Processes on Sulfides and Fe-Oxide Minerals on Asteroids
Sulfide nanoparticles have been observed in multiple grains returned from near-Earth asteroid 25143 Itokawa; Fe-sulfides, Fe-Ni-sulfides, and Fe-oxides dominate the nanoparticle population for ion irradiated / laser impacted carbonaceous chondritic meteorites. We propose a systematic investigation into the mechanistic origins of these optically active, sulfide nanoparticles, which significantly modify the optical 
properties of space weathered asteroidal regoliths. We propose laboratory studies simulating solar-wind and meteoritic impact weathering on individual accessory sulfide and oxide mineral grains present on asteroidal surfaces to investigate the formation kinetics of sulfide-nanoparticle. We propose to identify optical effects as a function of radiation flux and fluence, and identify the underlying microstructural effects and/or changes in surface chemistry. Solar-wind simulation will be carried out as a function of ion-species, fluence, flux, and target mineral, with changes in surface composition and chemistry quantified by X-ray photoelectron spectroscopy at the University of Virginia (UVa), as well as situ bidirectional reflectance measurements (phase angle: 30°) of sample mineralogy. UVa Research Component: Solar-wind type radiation processing using laboratory H and He ion irradiation and characterization of irradiation effects by X-ray photoelectron spectroscopy and visible-near infrared (Vis-NIR) reflectance.
PI: Michelle Thompson (Purdue University)
Co-I/UVa PI: Catherine Dukes (Research Scientist)
UVa Contributors: Kamil Stelmach (Chemistry PhD Student); Brian Richards (UVa-MechE Undergraduate); Logan Honts (UVa-Aerospace Undergraduate); Niquana Smith (MSE PhD Student); Kristyn Ardrey (MSE PhD Student).
Proceedings and Publications:
L. C. Chaves, M.S. Thompson, M. J. Loeffler, C.A. Dukes, P.S .Szabo, B.H. Horgan, “Evaluating the effects of space weathering on magnetite on airless planetary bodies,” Icarus, 402, 115634 (2023) https://doi.org/10.1016/j.icarus.2023.115634.
L. Chaves, M. Thompson, B. Horgan, C. Dukes, M. Loeffler, Investigating the Response of Sulfides and Fe- Oxides Under Space Weathering Conditions Through the Analysis of Returned and Experimental Samples, Microscopy & Microanalysis, 28, S1, 2698–2699 (2022) https://doi.org/10.1017/S1431927622010182
L. C. Chaves, M. S. Thompson, C.A. Dukes, M. J. Loeffler, B. Horgan, P. S. Szabo, N. L. Smith, and K. D. Ardrey, Evaluating the Effects of Space Weathering on Asteroidal Accessory Phases: Magnetite and Pentlandite, 54th LPSC Abstract# 1804 (2023)
L.C. Chaves, Thompson M.S., Horgan B., Dukes C.A., Loeffler M.J. 2022. Space Weathering of Magnetite Simulated by Pulsed Laser and Ion Irradiation Experiments. Abstract #6322. 85th Meteoritical Society Conference.
L. Chaves, M. Thompson, B. Horgan, C. Dukes, & M. Loeffler, Simulating Space Weathering on Magnetite via Pulsed Laser and Ion Irradiation Experiments, 23rd General Meeting of the International Mineralogical Association, 18 - 22 July 2022 Lyon, France, id: IMA2022-1744 (2022)
L. Chaves, M. Thompson, B. Horgan, C. Dukes, and M. Loeffler, Investigating the response of sulfides and Fe- oxides under space weathering conditions through the analysis of returned and experimental samples, Microscopy and Microanalysis Conference (2022)L. Chaves, M. Thompson, B. Horgan, C. Dukes, & M. Loeffler, Simulating Space Weathering on Magnetite via Pulsed Laser and Ion Irradiation Experiments, 23rd General Meeting of the International Mineralogical Association, 18 - 22 July 2022 Lyon, France, id: IMA2022-1744 (2022)
L. C. Chaves, M. S. Thompson, B. N. Horgan, C. A. Dukes, M. J. Loeffler, L. Honts, and B. Richards, Understanding the effects of space weathering on magnetite through experimental simulations, 53rd LPSC Abstract# XXXX (2022)
Theme:
Studying the interaction of energetic particles (ions, electrons and photons) with solid surfaces, with an emphasis on understanding the physical and chemical processes at play in our solar system and interstellar medium.