Electron densities for 10 planetary nebulae derived from the CIII 1907/1909 ratio. II.
Feibelman, W. A.; Hobbs, R. W.; Boggess, A.; McCracken, C. W.
United States
Abstract
Electron densities for IC 351, IC 2165, J900, IC 3568, NGC 6644, NGC 6891, IC 4997, NGC 7009, Hu 1-2, and IC 5217 are derived from high-dispersion semiforbidden C III spectrograms. For seven of these nebulae, the derived electron density is larger than the values derived from either surface brightness measurements or forbidden line ratios. Only one object, Hu 1-2, shows pronounced splitting of the semiforbidden C III emission lines due to a large expansion velocity.