Abstract
The composition of ices in comets may reflect that of the molecular cloud in which the Sun formed, or it may show evidence of chemical processing in the pre-planetary accretion disk around the proto-Sun. As carbon monoxide (CO) is ubiquitous in molecular clouds1,2, its abundance with respect to water could help to determine the degree to which pre-cometary material was processed, although variations in CO abundance may also be influenced by the distance from the Sun at which comets formed3,4,5. Observations have not hitherto provided an unambiguous measure of CO in the cometary ice (native CO). Evidence for an extended source of CO associated with comet Halley was provided by the Giotto spacecraft6,7,8,9, but alternative interpretations exist10. Here we report observations of comet HaleâBopp which show that about half of the CO in the comet comes directly from ice stored in the nucleus. The abundance of this CO with respect to water (12 per cent) is smaller than in quiescent regions of molecular clouds, but is consistent with that measured in proto-stellar envelopes11, suggesting that the ices underwent some processing before their inclusion into HaleâBopp. The remaining CO arises in the coma, probably through thermal destruction of more complex molecules.
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References
Rank, D. M., Townes, C. H. & Welch, W. J. Interstellar molecules and dense clouds. Science 174, 1083â1101 (1971).
Turner, B. E. Recent progress in astrochemistry. Space Sci. Rev. 51, 235â337 (1989).
Mumma, M. J. Organic volatiles in comets: Their relation to interstellar ices and solar nebula material. Astron. Soc. Pacif. Conf. Ser. 122, 369â396 (1997).
Mumma, M. J., Weissman, P. R. & Stern, S. A. in Protostars and Planets, III(eds Levy, E. H. & Lunine, J.I.) 1177â1252 (Univ. Arizona Press, Tucson, 1993).
Sandford, S. A. & Allamandola, L. J. The condensation and vaporization behavior of H2O:CO ices and implications for interstellar grains and cometary activity. Icarus 76, 201â224 (1988).
Eberhardt, P. et al. . The CO and N2 abundance in comet P/Halley. Astron. Astrophys. 187, 481â484 (1987).
Huebner, W. F., Boice, D. C. & Sharp, C. M. Polyoxymethylene in comet Halley. Astrophys. J. 320, L149âL152 (1987).
Huntress, W. T., Allen, M. & Delitsky, M. Carbon suboxide in comet Halley? Nature 352, 316â318 (1991).
Meier, R., Eberhardt, P., Krankowsky, D. & Hodges, R. R. The extended formaldehyde source in comet P/Halley. Astron. Astrophys. 277, 677â690 (1993).
Greenberg, J. M. & Li, A. From interstellar dust to comets: the extended CO source in comet Halley. Astron. Astrophys. 332, 374â384 (1998).
Chiar, J. E. et al. . Processing of icy mantles in protostellar envelopes. Astrophys. J. 498, 716â727 (1998).
Biver, N. et al. . Substantial outgassing of CO from comet HaleâBopp at large heliocentric distance. Nature 380, 137â139 (1996).
Biver, N. et al. . Evolution of the outgassing of comet HaleâBopp (C/1995 O1) from radio observations. Science 275, 1915â1918 (1997).
Womack, M., Festou, M. C. & Stern, S. A. The heliocentric evolution of key species in the distantly-active comet C/1995 O1 (HaleâBopp). Astron. J. 114, 2789â2795 (1997).
Greene, T. P., Tokunaga, A. T., Toomey, D. W. & Carr, J. S. CSHELL: A high spectral resolution 1â5âµm cryogenic echelle spectrograph for the IRTF. Proc. SPIE 1946, 311â324 (1993).
Dello Russo, N., DiSanti, M. A., Mumma, M. J., Magee-Sauer, K. & Rettig, T. W. Carbonyl sulfide in comets C/1996 B2 (Hyakutake) and C/1995 O1 (HaleâBopp): Evidence for an extended source in HaleâBopp. Icarus 135, 377â388 (1998).
Dello Russo, N. et al. . Direct detection of water in comet C/1995 O1 (HaleâBopp). Icarus(submitted).
Herzberg, G. Spectra of Diatomic Molecules(Van Nostrand Reinhold, New York, 1950).
Weaver, H. A. et al. . Infrared spectroscopy of comet HaleâBopp. Earth Moon Planets(in the press).
Lämmerzahl, P. et al. . Expansion velocity and temperatures of gas and ions measured in the coma of comet P/Halley. Astron. Astrophys. 187, 169â173 (1987).
Boice, D. C., Sablik, M. J. & Konno, I. Distributed coma sources and the CH4/CO ratio in Comet Halley. Geophys. Res. Lett. 17, 1813â1816 (1990).
Crifo, J. F. Ageneral physicochemical model of the inner coma of active comets. 1. Implications of spatially distributed gas and dust production. Astrophys. J. 445, 470â488 (1995).
Xie, X. & Mumma, M. J. Monte Carlo simulation of cometary Atmospheres: Application to Comet P/Halley at the time of the Giotto Spacecraft encounter. II. Axisymmetric model. Astrophys. J. 464, 457â475 (1996).
Combi, M. R. Time-dependent gas kinetics in tenuous planetary atmospheres: The cometary coma. Icarus 123, 207â226 (1996).
Xie, X. & Mumma, M. J. The effect of electron collisions on rotational populations of cometary water. Astrophys. J. 386, 720â728 (1992).
Biver, N. et al. . Long term evolution of the outgassing of comet HaleâBopp from radio observations. Earth Moon Planets(in the press).
Kunde, V. G. & Maguire, W. C. Adirect integration transmittance model. J. Quant. Spectrosc. Rad. Transf. 14, 803â817 (1974).
Rothman, L. S. et al. . The HITRAN molecular database: Editions of 1991 and 1992. J. Quant. Spectrosc. Rad. Transf. 48, 469â507 (1992).
Crovisier, J. Rotational and vibrational synthetic spectra of linear parent molecules in comets. Astron. Astrophys. Suppl. 68, 223â258 (1987).
Huebner, W. F., Keady, J. J. & Lyon, S. P. Solar photo rates for planetary atmospheres and atmospheric pollutants. Astrophys. Space Sci. 195, 1â294 (1992).
Green, S. F., McDonnell, J. A. M., Pankiewicz, G. S. A. & Zarnecki, J. C. in 20th ESLAB Symposium on the Exploration of Halley's Comet Vol. 2, 81â86 (SP-250, ESA, 1986).
Jewitt, D. & Matthews, H. E. Particulate mass loss from comet HaleâBopp. Astron. J. 117, 1056â1062 (1999).
Acknowledgements
This work was supported through the NASA Planetary Astronomy Program. We thank the staff of the NASA Infrared Telescope Facility for their support throughout our comet HaleâBopp observing campaign. The IRTF is operated by the University of Hawaii under contract to NASA. We thank J. Crovisier for comments which improved the manuscript.
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DiSanti, M., Mumma, M., Russo, N. et al. Identification of two sources of carbon monoxide in comet HaleâBopp. Nature 399, 662â665 (1999). https://doi.org/10.1038/21378
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DOI: https://doi.org/10.1038/21378
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