| Abstract: | Using published data on Hß-,λ4471 Hel- and λ4686 Hell-line fluxes for planetary nebulae the energy distribution in their nuclei is calculated in the wavelength range 100–912 Å by supposing that 1) the spectrum inclination is the same in the regions of continuous absorption of Hl, Hel, and Hell atoms; and 2) discontinuities at 504 Å and 228 Å are present in the nuclei spectra. From 40 investigated nebulae, only for two nuclei the distribution in all three intervals 504–912 Å, 228–504 Å and λ ≦ 228 Å corresponds to one and the same temperature of black-body emission. In 24 cases the emission temperature is the same for the first and the second interval. The energy distribution in the wavelength range shorter than 228 Å corresponds systematically to very high temperatures T* > 100,000 K. It is concluded that the emission temperature over the surface of nuclei is markedly inhomogeneous and/or the nuclei of planetary nebulae possess a hot corona. |
