SMALL-SCALE STRUCTURE OF THE GASEOUS NEBULAE

Using the intensities of the recombination lines, the abundances of carbon, nitrogen and oxygen for twenty-six gaseous nebulae have been determined. The abundances found exceed 2-10 times these determined from intensities of the lines excited by electron impact. The ratio of abundances obtained using the spectral lines formed by different dominating line-formation mechanisms can be considered as the measure of the electron temperature and density fluctuations. The influence of the fluctuations on the recombination line intensities and the intensities of the lines excited by electron impact have been investigated. It has been concluded that the electron temperature fluctuations affect strongly the results of element abundance determination, but the question about similar influence of the density fluctuations remains open. The size of the possible dense clumps in the nebulae have been estimated.