Self-consistent photoionization models of planetary nebulae luminescence: stellar ionizing continuum, nebular abundances, and evolution of the envelopes

A self-consistent photoionization model of PN luminescence is presented. The application of the model is illustrated for the PNs BD+30 3639 deg and NGC7293. The radial distributions of electron density, electron temperature, and other parameters in the nebular envelopes are found. The evolution of the radial distribution of gas density in the PN envelopes is studied. It is shown that envelope forms as a result of quiet evolution of the 'slow' stellar wind of the precursor stars. The radial distributions of gas density in the envelopes of young PN rule out the idea the PNs form due to rapid ejection of clear-cut envelope. A new method for determining PN abundance is proposed and simple approximate expressions for the determining of various abundance ratios are found. (AIAA)