MODELING AND DISTANCE DETERMINATION OF PLANETARY-NEBULAE

At present the lack of a good, generally accepted distance scare is th e major limitation in the study of Planetary Nebula (PN) evolution and their distribution. We describe our fully self-consistent method to d erive the physical parameters of a PN, including its distance, from a set of observables. For this we calculate various models and search fo r a best fit of the model predictions to the observables. An accurate determination of the angular diameter is important for a good distance determination. We think that we shall achieve an accuracy of 30% in d istance. We estimate the error in stellar temperature at less than 15% and the uncertainty in the abundances at 0.10 dex.