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The Chemical Composition of Cometary Nuclei

Published online by Cambridge University Press:  14 August 2015

L. M. Shul'man
L. M. Shul'man*
Affiliation:
Main Astronomical Observatory, Ukrainian Academy of Sciences, Kiev, U.S.S.R.

Abstract

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The probable parent-molecules of radicals such as C3 and N2+ are discussed, and it is concluded that cometary nuclei may contain complicated organic molecules, such as C3H4, CH2N2, and C4H2. It is suggested that these molecules are formed by radiation synthesis in solid phase. In a time interval of order 107 to 109 yr bombardment from cosmic rays would be expected to transform the chemical composition to a depth of 1 m. Solar cosmic rays do not penetrate as far, and as a result the surface layer of the nucleus can be enriched with unsaturated hydrocarbons. After a critical concentration of this explosive material is reached a further burst of solar cosmic rays can initiate an explosion and thus an outburst in the comet's brightness. This mechanism is the only one advanced to date that can explain the synchronism of the energy output over the whole nuclear surface.

Type
Part IV/Physical Processes in Comets
Information
Symposium - International Astronomical Union , Volume 45: The Motion, Evolution of Orbits and Origin of Comets , 1972 , pp. 265 - 270
Copyright
Copyright © Reidel 1972 

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