Fig. 1: Scanning transmission x-ray microscoy (STXM) and scanning transmission electron microscopy (STEM) imaging and x-ray absorption near-edge structure (XANES) spectroscopy of Ryugu insoluble organic matter (IOM).
From: Variations of organic functional chemistry in carbonaceous matter from the asteroid 162173 Ryugu
Each set of images in A–C are a correlated STXM image at 290 eV, a false-color map of organic functional chemistry (magenta = aromatic C=C at 285 eV; green = ketone C=O at 286.7 eV; blue = carboxyl COOH at 288.5 eV), and a high-angle annular dark field (HAADF) STEM image. A IOM from Chamber A sample A0106. B, C IOM from Chamber C sample C0107. D Hierarchical clustering dendrogram of fitted XANES spectra from Ryugu IOM samples A0106 and C0107. The length of horizontal lines indicates the distance between spectral locations in a 21-dimensional space determined by Gaussian peak fitting. Samples labeled with IOM denote average spectra of surrounding IOM in the vicinity of the discrete grains (excluding other discrete grains). E XANES spectra from individual discrete grains and nanoglobules in A–C, compared to bulk, fluffy-textured IOM from A0106 and C0107, as well as IOM from the Orgueil (CI) and Murchison (CM) carbonaceous chondrites.
