Figure 6.

The H isotopic compositions of water in various objects as a function of radial distance from the Sun. 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 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 approximately 3 AU and approximately 7 AU (arrowed). The formation locations of the comets are unknown, but are thought to have been between approximately 20 AU and approximately 30 AU (e.g. [92]). 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. Sources are given in tables 1 and 2, and Alexander et al. [23].