资源环境科技发展态势分析平台

Space weathering effects on the rocky S-class asteroids are well understood. However, on the low-albedo C-complex asteroids, such as spacecraft targets Bennu and Ryugu, the situation is more complicated, especially due to a lack of spectral features throughout the visible-near infrared spectral region. Here we show, through a combination of observational data and laboratory data of carbonaceous chondrites, phyllosilicates, and mixtures, that the UV-visible spectral region is a diagnostic regime for studying space weathering effects on C-complex asteroids. We show that space-weathering-produced opaque constituents, such as graphitized carbons, darken mixtures with phyllosilicates and produce a bluing the UV-visible spectrum, consistent with what is seen on the asteroids compared with carbonaceous chondrites. Furthermore, we demonstrate that the UV upturns in the spectra of Bennu and Ryugu are consistent with the presence of graphitized carbon on those surfaces, the result of surface processing.