title: Comet Halley as an aggregate of interstellar dust and further evidence for the photochemical formation of organics in the interstellar medium.
abstract: Photolysis of mixtures of CO:NH3:H2O at 12 K results in the formation of an organic residue which is not volatile in high vacuum at room temperature.  Analysis of this fraction by GC-MS resulted in the detection of C2-C3 hydroxy acids and hydroxy amides, glycerol, urea, glycine, hexamethylene tetramine, formamidine and ethanolamine.  Use of isotopically labeled gases made it possible to establish that the observed products were not contaminants.  The reaction pathways for the formation of these products were determined from the position of the isotopic labels in the mass spectral fragments.  The significance of these findings to the composition of comets and the origins of life is discussed.
authors.affiliation: Center for Laboratories and Research, N.Y. State Department of Health, Albany 12201.
authors.forename: R
authors.initials: R
authors.lastname: Briggs
authors.forename: G
authors.initials: G
authors.lastname: Ertem
authors.forename: J P
authors.initials: JP
authors.lastname: Ferris
authors.forename: J M
authors.initials: JM
authors.lastname: Greenberg
authors.forename: P J
authors.initials: PJ
authors.lastname: McCain
authors.forename: C X
authors.initials: CX
authors.lastname: Mendoza-Gomez
authors.forename: W
authors.initials: W
authors.lastname: Schutte
mesh_terms: D004391:Dust / Q000032:analysis*; D005118:Extraterrestrial Environment; D005740:Gases / Q000737:chemistry; D007554:Isotopes; D008956:Models, Chemical; D000069497:Origin of Life; D010777:Photochemistry; D010782:Photolysis; D016082:Solar System
chemical_list: D004391:Dust; D005740:Gases; D007554:Isotopes