Studies of southern planetary nebulae. II. Electron temperatures and densities

Electron temperatures and densities for 14 bright southern planetary nebulae, obtained from data previously published, are presented here. It is found that the difference between the logarithmic electron densities obtained from the ratio of nebular lines and from the ratio of auroral or transauroral lines to nebular lines is linearly correlated with the electron densities. It is also found that the ratio of the temperatures in the O III and N II forbidden line regions, T(H)/T(L), is linearly correlated with the degree of excitation, measured through the intensity of He II 4686A. The relation is double valued, with values of T(H)/T(L) both larger and smaller than 1 for the same degree of excitation. Up to this moment, no physical parameter giving a unique correlation with T(H)/T(L) has been found. 25 references