Synthetic post-asymptotic giant branch evolution: Basic models and applications to disk populations

We explore the realm of post-asymptotic giant branch (post-AGE) 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-e(R)), 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-e(R) indetermination produces very high indeterminations in the t(tr) and thus in the resulting post-AGE populations; and (3) the synthetic models give a test check for the ratio of He- to H-burning PNNs. In this paper, disk post-AGE populations are considered. Future applications will include Magellanic Cloud PNs and populations of bulges and elliptical galaxies.