Interstellar Organic Matter in Meteorites

We have inferred that many meteorites contain organic matter of interstellar origin in acid (HC1,HF) treated residues (Yang and Epstein, 1982, 1983b). Hydrogen in the acid soluble matter shows two different hydrogen sources (Yang and Epstein, 1983a). A direct relationship is found between the δD values of the hydrogen in acid soluble matter and the C/H ratios of the acid soluble matter in four meteorites. This suggests that for the two sources of the hydrogen, one has a C/H = 0 and δD ≃ -110‰ (phyllosilicates formed at T ≥ 200K) and the other has a C/H ≥ 2 and δD ≥10,000‰ (organic matter). The latter organic matter has a D/H ratio of about 0.002, comparable to the typical D/H values (Penzias, 1980) observed for the interstellar organic molecules in giant clouds. This supports an ion-molecule reaction mechanism (Watson, 1976; Smith et al., 1982) of the D-rich molecules in the meteorites.