Diverse space weathering effects on asteroid surfaces as inferred via laser irradiation of meteorites

作者：Pengfei Zhang, Kaiping Tai, Yang Li, J. Zhang, C. Lantz, T. Hiroi, M. Matsuoka, Shuang Li, Yangting Lin, Yuanyun Wen, Huijie Han, Xiaojia Zeng · 发表于：Astronomy and Astrophysics · 年份：2022 · DOI：10.1051/0004-6361/202142590 · 被引用次数：36 · 研究领域：Astro and Planetary Science、Planetary Science and Exploration、Laser-induced spectroscopy and plasma

Context. Space weathering (SW) is crucial to improve the understanding of the evolution of optical characteristics on airless bodies. The classical view based on research of the Moon suggests that SW decreases albedo (darkening) and steepens spectral slope (reddening) in visible to near-infrared (VIS-NIR) wavelengths, producing nanophase iron (npFe 0 ). However, this conclusion is not perfectly applicable to asteroids. Aims. In this study, we focus on investigating the space weathering spectral alteration effects (SWSAE) and the causes of spectral alteration on various types of asteroids after long-term continuous micrometeoroid bombardments. Methods. We used a pulsed laser to irradiate eight meteorites at the same energy, namely, of 28 mJ, in ten shots, including ordinary chondrites (OCs), aubrite (Aub), enstatite chondrites (ECs), CO, CV, and CM carbonaceous chondrites. Then we measured and compared the virgin and irradiated VIS-NIR reflectance spectra of these meteorites. We further surveyed the causes of spectral alteration through a scanning electron microscope and transmission electron microscope. Results. Three different SWSAE are shown: (1) darkening and reddening on OCs, Aub, CO, and CV chondrites; (2) brightening and reddening on ECs; (3) brightening and bluing on CM chondrite. After irradiation, npFe 0 and nanophase iron-nickel particles were respectively found in CV and CO chondrites; thick amorphous layers without any nanophase particles were found in Aub; meltin...