Measuring the shock stage of Itokawa and asteroid regolith grains by electron backscattered diffraction, optical petrography, and synchrotron X‐ray diffraction

• DOI: 10.1111/maps.13808
• Publication Date: 2022-04-08T02:51:16Z
• Authors: Michael Zolensky; James Martinez; Scott Sitzman; Takashi Mikouchi; Kenji Hagiya; Kazumasa Ohsumi; Mutsumi Komatsu; Tomoki Nakamura; Atsushi Takenouchi; Haruka Ono; Hikari Hasegawa; Kotaro Higashi; Yasuko Terada; Naoto Yagi; Masaki Takata; Hikaru Ozawa; Yuta Taki; Yuta Yamatsuta; Arashi Hirata; Ayaka Kurokawa; Shoki Yamaguchi
• Keywords: Regolith; Parent body

Abstract Our goal was to devise a bridge between shock determinations of asteroid regolith grains by standard light optical petrography, synchrotron X‐ray diffraction (SXRD), and electron backscattered (EBSD). We determined the optimal conditions under which measure stage olivine crystals in astromaterial EBSD. applied this EBSD procedure determination four from Itokawa, returned earth Hayabusa spacecraft. Interpretation these data required parallel examination three ordinary chondrite standards that exhibited histories ranging 2 4, using all techniques. Standard petrography indicated S2/3 for 24 Itokawa analyzed. SXRD results seven indicate S2. maps S3. Thus, different techniques slightly stages, probably due small sampling populations SXRD. therefore recommend significantly more than should be separately analyzed any technique, 10 20. In case, have been shocked S2/3, or approximately 5–10 GPa. Finally, we investigated crystallinity one SXRD, determining GPa it had experienced did not appreciably alter size unit cell, contrary some previous suggestions.