2000ApJ...542..308S

We explore the realm of post-asymptotic giant branch (post-AGB) stars from a theoretical viewpoint, by constructing a synthetic population of transition objects, proto-planetary nebulae, planetary nebula nuclei (PNNs), and post-planetary nebula objects. We use the Monte Carlo procedure to filter out the populations according to a given set of assumptions. We explore the parameter space by studying the effects of the initial mass function (IMF), the initial mass-final mass relation (IMFMR), the transition time (t_tr), the envelope mass at the end of the envelope ejection (M^R_e), the planetary nebula (PN) lifetime t_PN, and the hydrogen- and helium-burning phases of the central stars. The results are discussed on the basis of the H-R diagram distributions, the M_V-t plane, and mass histograms. We found that (1) the dependence of the synthetic populations on the assumed IMF and IMFMR is generally mild; (2) the M^R_e indetermination produces very high indeterminations in the t_tr and thus in the resulting post-AGB populations; and (3) the synthetic models give a test check for the ratio of He- to H-burning PNNs. In this paper, disk post-AGB populations are considered. Future applications will include Magellanic Cloud PNs and populations of bulges and elliptical galaxies.