Fig. 2: Transmission electron microscopy (TEM) and Scanning transmission x-ray microscopy (STXM) imaging and x-ray absorption near-edge structure (XANES) spectroscopy of carbonaceous grains in Ryugu fine-grained matrix.
From: Variations of organic functional chemistry in carbonaceous matter from the asteroid 162173 Ryugu
A TEM image of sample C0109-118 containing two carbonaceous grains (A1 and A2). B STXM false-color map of the same region showing the distinct organic functional chemistry of the two grains (magenta = aromatic C=C at 285 eV; green = ketone C=O at 286.7 eV; blue = carboxyl COOH at 288.5 eV). The surrounding phyllosilicate-rich matrix also contains diffuse C, visible as green and green-blue regions in this map. C High-angle annular dark field (HAADF) scanning TEM image of an alkyl-aromatic globular grain in a focused ion beam (FIB) section extracted from Ryugu particle A0108-3 (see Fig. 3). D XANES spectra of carbon grains and matrix shown in A–C. E Distribution of characteristic absorption peak area (plotted as a proportion of the total near-edge structure; see Methods) for carbonaceous grains and diffuse C in ultramicrotome and FIB sections. Solid color fields show the distributions for carbon grains identified in Ryugu insoluble organic matter (IOM) samples.
