title: Isotopic analysis of cometary organic matter.
abstract: Carbon isotope ratios have been measured for CN in the coma of comet Halley and for several CHON particles emitted by Halley.  Of these, only the CHON-particle data may be reasonably related to organic matter in the cometary nucleus, but the true range of 13C/12C values in those particles is quite uncertain.  The D/H ratio in H2O in the Halley coma resembles that in Titan/Uranus.  The next decade should substantially improve our understanding of the distribution of C, H, N, and O isotopes in cometary organics.  The isotopic composition of meteoritic organic matter is better understood and can serve as a useful analog for the cometary case.
authors.affiliation: Institute of Geophysics, University of California, Los Angeles 90024-1567, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Kerridge
mesh_terms: D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes; D055598:Chemical Phenomena; D002621:Chemistry; D003486:Cyanides / Q000032:analysis; D005118:Extraterrestrial Environment; D019110:Meteoroids; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes; D010100:Oxygen / Q000032:analysis*; D010103:Oxygen Isotopes; D016082:Solar System; D013696:Temperature
chemical_list: D002247:Carbon Isotopes; D003486:Cyanides; D009587:Nitrogen Isotopes; D010103:Oxygen Isotopes; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen