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Isotopic Ratios in Comets

Published online by Cambridge University Press:  12 April 2016

V. Vanysek
V. Vanysek*
Affiliation:
Astronomical Institute of University Erlangen—NuernbergDr.—Remeis—Observatory8600 Bamberg, F.R.G.

Abstract.

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The isotopic abundances depend on the universal evolution of elements and on the individual history of particular objects. Since it is believed that unprocessed material of the solar nebula is preserved in comets, the data concerning the abundance of stable isotopes in these primitive bodies are of some importance in the cosmological context. The present status of this problem is reviewed. The reliability of results for nuclear species with cosmological and cosmogonical implications, such as D/H, C 12/13, N 14/15, O 16/18, and Mg 24/25/26, is discussed. Significant variation is found for the isotopic abundance of carbon, depending upon which carbon reservoir is sampled. Deuterium is probably enhanced relative to the interstellar ratio. For other isotopes, the ratios are close to those of the terrestrial data. The tendency of the D/H ratio to be at higher values indicates a low temperature in the environment of the comet’s formation, and, together with similar effects in the outer planets, suggests that there were two different primordial reservoirs of deuterium in the solar system. The 12C/13C ratio inferred from in situ mass spectrometry of the dust, as well as from the ground-based optical spectra of the Swan band, tends to be approximately equal to the average terrestrial ratio (89) or larger. Recent results obtained from the CN band provide a significantly lower value (about 65), which corresponds to the carbon isotopic ratio in the diffuse interstellar clouds. The enhancement of deuterium and the possible differences of the carbon isotopic ratio in different species and refractory material are indicative of chemical fractionation processes in the protosolar nebula.

Type
Section V: The Cometary Coma
Information
International Astronomical Union Colloquium , Volume 116 , Issue 2: Comets in the Post-Halley Era , 1991 , pp. 879 - 895
Copyright
Copyright © Kluwer 1991

References

A’Hearn, M.F., Schleicher, D.G., and West, R.A. (1985). “Emission by OD in comets.” Astrophys. J. 297, 826.Google Scholar
Allamandola, L.J., Sandford, S.A., and Wopenka, B. (1987). “Interstellar polycyclic aromatic hydrocarbons and carbon in interplanetary dust particles and meteorites.” Science 237, 56.Google Scholar
Anders, E. (1987). “Local and exotic components of primitive meteorites and their origin.” Phil. Trans. R. Soc. London, A 323, 287.Google Scholar
Audouze, J. (1977). “Importance of CNO isotopes in astrophysics.” In CNO Isotopes in Astrophysics, Audouze, J. et al. (eds.), Reidel, D., Dordrecht, p. 155.CrossRefGoogle Scholar
Bastien, P., Bartla, W., Henkel, C., Paulus, T., Walmsley, C.M., and Wilson, T.L. (1985). “Formaldehyde observation in OMC-1.” Astron. Astrophys. 149, 86.Google Scholar
Beer, R., and Taylor, F.W. (1973). “The D/H and C/H ratios in Jupiter.” Astrophys. J. 219, 763.CrossRefGoogle Scholar
Black, D.C. (1973). “Deuterium in the early solar system.” Icarus 19, 154.Google Scholar
Brown, P.D., and Millar, T.J. (1989a). “Models of the gas-grain interaction deuterium chemistry.” Month. Not. RAS 237, 661.Google Scholar
Brown, P.D., and Millar, T.J. (1989b). “Grain-surface formation of multi-deuterated molecules.” Month. Not. RAS 240, 25.CrossRefGoogle Scholar
Brown, R.D., and Rice, E.H.N. (1986). “Galactochemistry II, interstellar deuterium chemistry.” Month. Not. RAS 223, 429.CrossRefGoogle Scholar
Combes, F., Falgarone, E., Guibert, J., and Nguyen-Q-Rieu, (1980). “CO observations of interstellar clouds: Isotopic ratios.” Astron. Astrophys. 90, 88.Google Scholar
Danks, A.C., Lambert, D.L., and Arpigny, C. (1974). “The 12C/13C ratio in comet Kohoutek (1973 f).” Astrophys. 194, 745.CrossRefGoogle Scholar
de Bergh, C., Lutz, B.L., Owen, T., Brault, J., and Chauville, J. (1986). “Monodeuterated methane in the outer solar system. II. Its detection on Uranus at 1.6 μm.” Astrophys. J. 311, 501.CrossRefGoogle Scholar
de Bergh, C., Lutz, B.L., and Owen, T. (1988). “Monodeuterated methane in the outer solar system. III. Its abundance on Titan.” Astrophys. J. 329, 951.CrossRefGoogle Scholar
de Bergh, C., Lutz, B.L., and Owen, T. (1989). “Monodeuterated methane in the outer solar system. IV. Its detection and abundance on Neptune.” Astrophys. J., in press.Google Scholar
Eberhardt, P., Krankowsky, D., Schulte, W., Dolder, U., Laemmerzahl, P., Bertheier, J.J., Woweries, J., Stubbemann, U., Hodges, R.R., Hoffmann, J.H., and Illiano, J.M. (1987). “The D/H ratio in water from comet P/Halley.” Astron. Astrophys. 187, 435.Google Scholar
Encrenaz, T. (1984). “Isotopic ratios in comets.” In Isotopic Ratios in the Solar System, Cepadeus-Edition, Toulouse, p. 173.Google Scholar
Gautier, D., and Owen, T. (1983). “Cosmological implication of elemental and isotopic abundances in atmospheres of Jovian planets.” pNature 302, 215.Google Scholar
Geiss, J. (1988). “Composition in Halley’s comet: Clues to origin and history of cometary matter.” In Reviews of Modern Astronomy 1, Klare, G. (ed.), Springer-Verlag, Heidelberg, p. 1.Google Scholar
Geiss, J., and Reeves, H. (1972). “Cosmic and solar system abundance of deuterium and helium 3.” Astron. Astrophys. 18, 126.Google Scholar
Geiss, J., and Reeves, H. (1981). “Deuterium in the solar system.” Astron. Astrophys. 93, 189.Google Scholar
Gerin, J., Combez, F., Encrenaz, P., Linke, R., Destombes, J.L., and Demuynck, C. (1984). “Detection of 13CN in three galactic sources.” Astron. Astrophys. 136, L17.Google Scholar
Grinspoon, D., and Lewis, J.S. (1987). “Deuterium fractionation in the presolar nebula.” Icarus 78, 430.Google Scholar
Hawkins, I., and Jura, M. (1987). “The 12C/13C isotope ratio of the interstellar medium in the neighborhood of the sun.” Astrophys. J. 317, 926.Google Scholar
Herbst, E. (1988). “Interstellar molecular formation process.” In Reviews of Modern Astronomy 1, Klare, G. (ed.), Springer-Verlag, Heidelberg, p. 114.Google Scholar
Hubbart, W.B., and McFarlane, J.J. (1980). “Theoretical prediction of deuterium abundance in Jovian planets.” Icarus 44, 676.Google Scholar
Ip, W.-H. (1985). “Condensations and agglomeration of cometary ice: The HDO/HO ratios as traces.” In Ices in the Solar System, Klinger, J. et al. (eds.), Reidel, D., Dordrecht, p. 389.Google Scholar
Jessberger, E.K. (1990). “Chemical properties of cometary dust and a note on carbon isotopes.” In this volume.Google Scholar
Jessberger, E.K., Kissel, J., Fechtig, H., and Krueger, F.R. (1986). “On average chemical composition of cometary dust.” ESA Spec. Publ. 249, 27.Google Scholar
Krankowsky, D., Eberhardt, P., Dolder, U., Schulte, W., Laemmerzahl, P., Hoffmann, J.H., Hodges, R.R., Berthelier, J.J., and Illiano, J.M. (1986). “In-situ gas and ion measurements at Comet Halley.” Nature 321, 326.Google Scholar
Krishna Swamy, K.S. (1987). “Study of isotope features of Swan bands in comets.” Astron. Astrophys. 187, 388.Google Scholar
Lambert, D.L., and Danks, A.C. (1983). “High resolution spectra of C2 Swan bands from comet West.” Astrophys. J. 268, 428.CrossRefGoogle Scholar
Langer, W.D., and Graedel, T.E. (1989). “Ion-molecule chemistry of dense clouds.” Astrophys. J. Suppl. 69, 241.Google Scholar
Langer, W.D., Graedel, T.E., Frerking, M.A., and Armentroud, J. (1984). “Carbon and oxygen isotope fractionation in dense interstellar clouds.” Astrophys. J. 277, 587.Google Scholar
Lutz, B.L., de Bergh, C., and Maillard, J.P. (1983). “Monodeuterated methane in outer solar system I.” Astrophys. J. 273, 397.Google Scholar
Lutz, B.L., Owen, T., and de Bergh, C. (1989). “Deuterium enrichment in primitive ices of the solar nebula.” Lowell Observatory Preprints.Google Scholar
McKeegan, K.D., Walker, R.M., and Zinner, E. (1985). “Ion microprobe isotopic measurements of individual interplanetary dust particles.” Geochim. Cosmochim. Acta, 49.Google Scholar
Millar, T.J., Bennet, A., and Herbst, E. (1989). “Deuterium fractionation in dense interstellar clouds.” Astrophys. J. 340, 906.Google Scholar
Owen, T., Lutz, B.L., and de Bergh, C. (1986). “Deuterium in the outer solar system.” Nature 320, 224.CrossRefGoogle ScholarPubMed
Pasachoff, J.M., and Vidal-Madjar, A. (1989). “The need to observe the distribution of interstellar deuterium.” Comments in Astrophysics 14, 61.Google Scholar
Penzias, A.A. (1983). “Measurement of isotopic abundances in interstellar clouds.” In Interstellar Molecules, Andrew, B.H. (ed.), Reidel, D., Dordrecht, p. 397.Google Scholar
Pillinger, C.T. (1987). “Stable isotope measurements of meteorites and cosmic dust grains.” Phil. Trans. R. Soc. London A 323, 313.Google Scholar
Robert, F., Melivat, L., and Javoy, M. (1979). “Water and deuterium content in the Chainpur and Orgueil meteorites.” Nature 289, 785.Google Scholar
Sarmiento, A., and Peimebert, M. (1985). “Novae and galactic chemical evolution.” Rev. Mexicana Astr. Astrophys. 11, 73.Google Scholar
Singh, P.D., and Dalgarno, A. (1987). “Photodissociation lifetimes of CH and CD radicals in comets.” ESA Spec. Publ. 278, 177.Google Scholar
Smith, D. (1987). “Interstellar molecules.” Phil. Trans. R. Soc. London A 323, 269.Google Scholar
Smith, H.W., Schempp, W.V., and Baines, K.H. (1989). “D/H for Uranus and Neptune.” Astrophys. J. 336, 976.Google Scholar
Sole, M., Vanysek, V., and Kissel, J. (1987). “Carbon-isotope ratio in PUMA 1 spectra ofP/Halley.” Astron. Astrophys. 187, 385.Google Scholar
Stawikowski, A., and Greenstein, J.L. (1964). “Isotope ratio 12C/13C in a comet.” Astrophys. J. 140, 1280.CrossRefGoogle Scholar
Swart, P.K., Grady, M.M., Pillinger, C.T., Lewis, R.S., and Anders, E. (1983). “Interstellar carbon in meteorites.” Science 200, 406.Google Scholar
Tielens, A.G.G.M. (1983). “Surface chemistry of deuterated molecules.” Astron. Astrophys. 119, 177.Google Scholar
van Dishoeck, E.F., and Black, J.H. (1988). “Diffuse cloud chemistry.” In Rate Coefficients in Astrochemistry, Millar, T. J. and Williams, D.A. (eds.), Kluwer Academic Press, Dordrecht, p. 209.Google Scholar
Vanysek, V. (1977). “Carbon isotope ratio in comets and interstellar matter.” In Comets, Asteroids and Meteorites, Delsemme, A.H. (ed.), University of Toledo Press, Toledo, p. 499.Google Scholar
Vanysek, V., and Rahe, J. (1978). “The carbon isotopes in comets.” Moon and Planets 18, 441.Google Scholar
Vanysek, V., and Vanysek, P. (1985). “Prediction of deuterium abundance in comets.” Icarus 61, 57.CrossRefGoogle Scholar
Vidal-Madjar, A. (1983). “Interstellar helium and deuterium.” In Diffuse Matter in Galaxies, Audouze, J. et al. (eds.), Reidel, D., Dordrecht, p. 57.Google Scholar
Wyckoff, S., Lindholm, E., Wehinger, P.A., Peterson, B.A., Zucconi, J.M., and Festou, M.C. (1989). “The 12C/13C abundance ratio in Comet Halley.” Astrophys. J. 339, 488.Google Scholar
Yang, J., and Epstein, S. (1983). “On the origin and composition of hydrogen and carbon in meteorites.” Geochim. Cosmochim. Acta 47, 2199.Google Scholar
Zucconi, J.M., and Festou, M.C. (1986). “The isotopes of CN in comets.” Astron. Astrophys. 158, 382.Google Scholar