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Composition and Origin of Cometary Materials pp 19–32Cite as

Remote Observations of the Composition of Cometary Volatiles

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Part of the book series: Space Science Series of ISSI ((SSSI,volume 8))

Abstract

The volatile species released in the coma are an important clue to the composition of the cometary nucleus ices. Their identification and the measurement of their abundances is possible by remote sensing. Considerable progress has been made recently using radio and infrared spectroscopy, especially with the observations of the two exceptional comets C/1996 B2 (Hyakutake) and C/1995 01 (Hale-Bopp).) 24 molecules likely to be parent molecules outgassed from the nucleus have now been identified. Significant upper limits exist for many other species, and the presence of unidentified lines suggests that further species are to be identified. In addition, isotopic varieties have been observed for hydrogen, carbon, nitrogen and sulphur. We will review these results with a special emphasis on the reliability of the identifications and of the molecular production rate determinations. A critical point is to assess whether a given species is a genuine parent molecule outgassed from nuclear ices, or is a secondary product coming from grains or from gas-phase photochemistry. Ground-based spectral imaging, such as radio interferometry, may help resolving this problem.

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  1. Observatoire de Paris-Meudon, F-92195, Meudon, France

    J. Crovisier & D. Bockelée-Morvan

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  1. J. Crovisier
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  2. D. Bockelée-Morvan
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Editors and Affiliations

  1. Physikalisches Institut, Universität Bern, CH-3012, Bern, Switzerland

    K. Altwegg

  2. Leiden Observatory, 2300 RA, Leiden, The Netherlands

    P. Ehrenfreund

  3. International Space Science Institute, CH-3012, Bern, Switzerland

    J. Geiss

  4. Southwest Research Institute, San Antonio, TX, 78228-0510, USA

    W. F. Huebner

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Crovisier, J., Bockelée-Morvan, D. (1999). Remote Observations of the Composition of Cometary Volatiles. In: Altwegg, K., Ehrenfreund, P., Geiss, J., Huebner, W.F. (eds) Composition and Origin of Cometary Materials. Space Science Series of ISSI, vol 8. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4211-3_2

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