Estimated H/C. (a) Carbonaceous chondrite IOM band depth at 3.42 μm, plotted against H/C (atom.) from Alexander et al. (2007); “other” refers to IOM from CV, CO, CR, and ungrouped carbonaceous chondrites. The 3.42 μm band depths from OVIRS Recon A average (red diamond) and organic-rich spectra (blue diamonds) are plotted on the IOM trend to estimate the upper limit on H/C of 0.6 for Bennu. (b) Carbonaceous chondrite (i.e., bulk meteorite) band depth at 3.42 μm plotted against wt.% C for those meteorites; the symbology is the same as in panel a but for bulk meteorites as opposed to IOM (gray triangle, CM-type; gray cross, CI-type; gray square, heated CM-type; gray circle, other carbonaceous chondrite IOM, including CV, CO, CR, and ungrouped). The band depth at 3.42 μm is also shown for OVIRS organic-rich (blue shaded region) and Bennu global average spectra (solid red line; standard deviation, dashed red lines). The Bennu organic-rich spectra have similar band depths to carbonaceous chondrites containing 1−2.5 wt.% C. (c) Combination of wt.% C and H/C of IOM, the best predictor of 3.42 μm band depth in the meteorites.