Fig. 3. Multiband colors of Ryugu’s surface.

(A) Comparison between disk-averaged spectra (lines with squares, normalized at 0.55 μm) for Ryug at 12 different rotational phases and ground-based observations (lines without symbols) of Ryugu from (55) (blue) and from (21) (red). Data are also shown for the large main-belt asteroids Polana, Eulalia, and Erigone (56), each of which is the parent body of an asteroid family. Because of the similarity among the spectra taken at different phases, individual lines for Ryugu overlap. Spectra are offset by 0.1 for clarity. (B) Comparison between typical Ryugu surface colors (black) (reflectance factor at 30°, 0°, 30°) and those of dehydrated CCs (blue) and typical CCs (red). Individual meteorite names are indicated. The spectrum of a powder sample (≤155 μm) of Jbilet Winselwan was measured at 30°, 0°, 30° with the spectrometer system at Tohoku University (57). The rest of meteorite spectra are from (58). (C) Reflectance spectra of typical morphologic and color features on Ryugu. Locations of features (labeled 1 to 6) are shown in (E) and (F) and in fig. S12. Individual spectra are shifted vertically for clarity. Vertical-axis tick spacing is 0.05%. (D) Same as (C), but normalized by the Ryugu average spectrum. Vertical-axis tick spacing is 0.01. (E) b-x slope map (inverse micrometers) and (F) v-band reflectance factor map (percent) superposed on a v-band image map. The equatorial ridge and the western side (160°E to 290°E) have slightly higher v-band reflectances than other regions (see fig. S13 for statistical analysis).