Statistical survey of planetary nebulae: distances, masses, and distribution in the Galaxy

A new empirical scale of distances to planetary nebulae (PNs) is presented based on the interdependence between the PN diameter and the value of the surface brightness in the radio range. The dependence of the mean electron density in PNs on the diameter is determined, and the masses of the ionized matter in PNs are estimated. The variation of the properties of PNs as a function of the type of stellar population to which they belong is investigated, and the frequency of PN formation in the Galaxy is evaluated and compared with that of white dwarf formation. Finally, the dependence of the PN expansion velocity on linear size is defined.