LOCAL SPACE DENSITY AND FORMATION RATE OF PLANETARY-NEBULAE

Individual distances of 50 nearby planetary nebulae are determined usi ng a variety of methods, but excluding statistical methods or distance scales. These distances, together with a discussion of the sample com pleteness, are used to determine local PN formation rate. Together wit h the brightness of the nebula, its ionized mass is derived. The evolu tion of the ionized mass is discussed. As a by-product, the Zanstra te mperature of the central stars of the optically thick nebulae is found . Interestingly this temperature indicates that the DA white dwarfs in the sample are considerably hotter than previously thought. Finally, with the help of the galactic bulge PN, a luminosity function for PN i n the galaxy is derived.