Hostname: page-component-797576ffbb-42xl8 Total loading time: 0 Render date: 2023-12-09T22:34:14.737Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "useRatesEcommerce": true } hasContentIssue false

Insights into the nature of cometary organic matter from terrestrial analogues

Published online by Cambridge University Press:  04 January 2012

Richard W. Court*
Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College, London SW7 2AZ, UK
Mark A. Sephton
Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College, London SW7 2AZ, UK


The nature of cometary organic matter is of great interest to investigations involving the formation and distribution of organic matter relevant to the origin of life. We have used pyrolysis–Fourier transform infrared (FTIR) spectroscopy to investigate the chemical effects of the irradiation of naturally occurring bitumens, and to relate their products of pyrolysis to their parent assemblages. The information acquired has then been applied to the complex organic matter present in cometary nuclei and comae. Amalgamating the FTIR data presented here with data from published studies enables the inference of other comprehensive trends within hydrocarbon mixtures as they are progressively irradiated in a cometary environment, namely the polymerization of lower molecular weight compounds; an increased abundance of polycyclic aromatic hydrocarbon structures; enrichment in 13C; reduction in atomic H/C ratio; elevation of atomic O/C ratio and increase in the temperature required for thermal degradation. The dark carbonaceous surface of a cometary nucleus will display extreme levels of these features, relative to the nucleus interior, while material in the coma will reflect the degree of irradiation experienced by its source location in the nucleus. Cometary comae with high methane/water ratios indicate a nucleus enriched in methane, favouring the formation of complex organic matter via radiation-induced polymerization of simple precursors. In contrast, production of complex organic matter is hindered in a nucleus possessing a low methane/water ration, with the complex organic matter that does form possessing more oxygen-containing species, such as alcohol, carbonyl and carboxylic acid functional groups, resulting from reactions with hydroxyl radicals formed by the radiolysis of the more abundant water. These insights into the properties of complex cometary organic matter should be of particular interest to both remote observation and space missions involving in situ analyses and sample return of cometary materials.

Research Article
Copyright © Cambridge University Press 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Bar-Nun, A., Pat-El, I. & Laufer, D. (2007). Icarus 187(1), 321325.Google Scholar
Bernstein, M.P., Allamandola, L.J. & Sandford, S.A. (1997). Adv. Space Res. 19, 991998.Google Scholar
Brownlee, D.E., Horz, F., Newburn, R.L., Zolensky, M., Duxbury, T.C., Sandford, S.A., Sekanina, Z., Tsou, P., Hanner, M.S., Clark, B.C. et al. (2004). Science 304(5678), 17641769.Google Scholar
Cottin, H., Gazeau, M.C. & Raulin, F. (1999). Planet. Space Sci. 47(8–9), 11411162.Google Scholar
Court, R.W. & Sephton, M.A. (2009a). Geochim. Cosmochim. Acta 73(11), 35123521.Google Scholar
Court, R.W. & Sephton, M.A. (2009b). Anal. Chim. Acta 639, 6266.Google Scholar
Court, R.W., Sephton, M.A., Parnell, J. & Gilmour, I. (2006). Geochim. Cosmochim. Acta 70(4), 10201039.Google Scholar
Court, R.W., Sephton, M.A., Parnell, J. & Gilmour, I. (2007). Geochim. Cosmochim. Acta 71(10), 25472568.Google Scholar
Crovisier, J. (2006). The molecular composition of comets and its interrelation with other small bodies of the Solar System. In Asteroids, Comets, Meteors, ed. Daniela, L., Sylvio Ferraz, M. & Angel, F.J., pp. 133152. Cambridge University Press, Cambridge.Google Scholar
Davidson, C.F. & Bowie, S.H.U. (1951). Bull. Geol. Soc. Great Britain 3, 118.Google Scholar
Gibb, E.L., Mumma, M.J., Dello Russo, N., DiSanti, M.A. & Magee-Sauer, K. (2003). Icarus 165(2), 391406.Google Scholar
Greenberg, J.M. (1993). Physical and chemical composition of comets – from interstellar space to the Earth. In Chemistry of Life's Origins, ed. Greenburg, J.M. & Pirronello, V., pp. 195207. Kluwer, Dordrecht, The Netherlands.Google Scholar
Grip, E. & Ödman, O.H. (1944). Sveriges Geologiska Undersokning Serie C 38(6), 219.Google Scholar
Hudson, R.L. & Moore, M.H. (1997). Icarus 126(1), 233235.Google Scholar
Hudson, R.L. & Moore, M.H. (1999). Icarus 140(2), 451461.Google Scholar
Huebner, W.F. (2002). Earth Moon Planets 89(1–4), 179195.Google Scholar
Kadono, T., Sugita, S., Sako, S., Ootsubo, T., Honda, M., Kawakita, H., Miyata, T., Furusho, R. & Watanabe, J. (2007). Astrophys. J. 661(1), L89L92.Google Scholar
Kissel, J., Krueger, F.R. & Roessler, K. (1997). Organic chemistry in comets from remote and in situ observations. In Comets and the Origin and Evolution of Life, ed. Thomas, P.J., Chyba, C. & McKay, C.P., pp. 69109. Springer-Verlag, New York.Google Scholar
Kríbek, B., Zak, K., Spangenberg, J., Jehlicka, J., Prokes, S. & Kominek, J. (1999). Econ. Geol. 94(7), 10931114.Google Scholar
Landais, P., Dubessy, J., Dereppe, J.M. & Philp, R.P. (1993). Can. J. Earth Sci. 30(4), 743753.Google Scholar
Leventhal, J.S. & Threlkeld, C.N. (1978). Science 202(4366), 430432.Google Scholar
Moore, M.H. & Hudson, R.L. (1998) Icarus 135(2), 518527.Google Scholar
Nelson, R.M., Soderblom, L.A. & Hapke, B.W. (2004). Icarus 167(1), 3744.Google Scholar
Oberst, J., Giese, B., Howington-Kraus, E., Kirk, R., Soderblom, L., Buratti, B., Hicks, M., Nelson, R. & Britt, D. (2004). Icarus 167(1), 7079.Google Scholar
Parnell, J. (1985). Neues Jahrb. Geol. Palaeontol. Monatsh. 3, 132144.Google Scholar
Parnell, J. (1989). Aust. Mineral. 4, 145148.Google Scholar
Podolak, M. & Prialnik, D. (1996). Planet. Space Sci. 44(7), 655664.Google Scholar
Prialnik, D. & Mekler, Y. (1991). Astrophys. J., 366(1), 318323.Google Scholar
Radcliff, S. (1906). Trans. R. Soc. South Aust. 30, 199204.Google Scholar
Ryan, J.M., Lockwood, J.A. & Debrunner, H. (1999). Space Sci. Rev. 93(1–2), 3553.Google Scholar
Sandford, S.A., Aleon, J., Alexander, C.M.O., Araki, T., Bajt, S., Baratta, G.A., Borg, J., Bradley, J.P., Brownlee, D.E., Brucato, J.R. et al. (2006). Science 314(5806), 17201724.Google Scholar
Schulz, R. (2006). Compositional coma investigations: Gas and dust production rates in comets. In Asteroids, Comets, Meteors, ed. Daniela, L., Sylvio Ferraz, M. & Angel, F.J., pp. 413423. Cambridge University Press, Cambridge.Google Scholar
Strazzulla, G. (1997). Adv. Space Res. 19, 10771084.Google Scholar
Strazzulla, G. (1999). Space Sci. Rev. 90(1–2), 269274.Google Scholar
Strazzulla, G. & Palumbo, M.E. (1998). Planet. Space Sci. 46(9–10), 13391348.Google Scholar
Sunshine, J.M., A'Hearn, M.F., Groussin, O., Li, J.Y., Belton, M.J.S., Delamere, W.A., Kissel, J., Klaasen, K.P., McFadden, L.A., Meech, K.J. et al. (2006). Science 311(5766), 14531455.Google Scholar
Thomas, P.C., Veverka, J., Belton, M.J.S., Hidy, A., A'Hearn, M.F., Farnharn, T.L., Groussin, O., Li, J.Y., McFadden, L.A., Sunshine, J. et al. (2007). Icarus 187(1), 415.Google Scholar