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A recently generated theoretical line list of C II dielectronic recombinationlines together with observational data gathered from the literature is used toinvestigate the electron temperature in a range of astronomical objects, mainlyplanetary nebulae. The electron temperature is obtained by a least-squaresoptimisation using all the reliable observed lines in each object. In addition,the subset of lines arising directly from autoionising states is used todirectly determine the free-electron energy distribution which is then comparedwith various theoretical possibilities. The method described here canpotentially determine whether there are departures from Maxwell-Boltzmanndistributions in some nebulae, as has been recently proposed. Using publishedobservations of the three planetary nebulae where the relevant lines arerecorded, we find that the data are best matched by Maxwell-Boltzmanndistributions but that the uncertainties are sufficiently large at present thatkappa-distributions or two-component nebular models are not excluded.

Electron Temperatures and Free-Electron Energy Distributions of Nebulae from C II Dielectronic Recombination Lines