Histograms of the H/C atomic ratios as deduced by COSIMA for 33 cometary particles of 67P for the ion registration mode (positive mode in red in the first panel, negative mode in blue in the second panel), and the H/C ratio measured in 22 IOM samples extracted from CI, CM, and CR carbonaceous chondrites (in green in the third panel) and in 4 IOM samples from ordinary chondrites (in purple in the fourth panel). All H/C atomic ratios of the IOM samples of chondrites were measured by Alexander et al. (2007).