Figure 5.

The H isotopic compositions of OH/water in various objects as a function of radial distance from the Sun (modified after Alexander 2017). The H isotopic composition of methane in Titan’s atmosphere is also shown, although it is not known how closely it reflects that of the water that Titan accreted. The locations of the asteroidal parent bodies of the carbonaceous chondrites are not known and so they have been given nominal radial distances of 3 AU. Saturn’s moons Titan and Enceladus have been given their current orbital distances, although if there was a Grand Tack they may have formed between ~3 AU and ~7 AU (double arrowed). The formation locations of the comets are unknown, but are thought to have been between ~20 AU and ~30 AU (e.g., Brasser and Morbidelli 2013). The Oort (light grey) and Jupiter family (dark grey) comets are plotted at 30 AU and 20 AU, respectively, but their overlapping D/H ratios suggest that they formed in similar regions of the disk. With the possible exception of the CRs, the carbonaceous chondrite with the most D-rich water, the carbonaceous chondrites have compositions that are distinct from any measured outer Solar System body. Data sources are given in Tables 4 and 5.