FILLING FACTORS AND IONIZED MASSES IN PLANETARY-NEBULAE

We calculate filling factors (epsilon) and ionized masses (M(i)) for a total of 84 galactic and extragalactic planetary nebulae (PNe) at kno wn distances. To do these calculations, from the equation of energy pr opagation within a gaseous nebula, we have chosen forbidden line elect ron densities, observed angular diameters, and Hbeta fluxes, from the most recent measurements available in the literature. Statistical anal ysis on the distributions of E and M(i) show that (1) the range of val ues of these parameters is wider than what was previously found; (2) t he mean value of the filling factor is between 0.3 and 0.4, for the di fferent sets; (3) the mean value of the ionized mass is between 0.1 an d 0.25 M., 0.2 M. representing an upper limit to the ionized mass for galactic disk PNe, and a typical value for galactic bulge and extragal actic PNe; (4) a clear correlation between E and the dimensions of the PNe was not found when distance-independent sets of PNe were used; (5 ) for extragalactic PNe, where distance errors are not a factor, the f illing factors and the ionized masses anticorrelate tightly with the e lectron densities. The results indicate that the modified Shklowsky di stance method is correct.