Revised Simulations of the Planetary Nebulae Luminosity Function

TL;DR

This paper introduces an improved numerical simulation method for planetary nebulae luminosity functions using updated stellar evolution models, addressing optical thickness assumptions and explaining observed luminosity function variations.

Contribution

It presents a revised simulation procedure based on new post-AGB tracks, incorporating optical thinness and dust effects to better match observations.

Findings

New simulations suggest lower PN formation rates.

Optically thin PNs are necessary to match observations.

Variety in PNLF shapes explained by final mass range.

Abstract

We describe a revised procedure for the numerical simulation of planetary nebulae luminosity functions (PNLF), improving on previous work (M\'endez & Soffner 1997). The procedure now is based on new H-burning post-AGB evolutionary tracks (Miller Bertolami 2016). For a given stellar mass, the new central stars are more luminous and evolve faster. We have slightly changed the distribution of the [OIII] 5007 intensities relative to those of H$\beta$ and the generation of absorbing factors, while still basing their numerical modeling on empirical information extracted from studies of galactic planetary nebulae (PNs) and their central stars. We argue that the assumption of PNs being completely optically thick to H-ionizing photons leads to conflicts with observations and show that to account for optically thin PNs is necessary. We then use the new simulations to estimate a maximum final mass, clarifying its meaning, and discuss the effect of internal dust extinction as a possible way of explaining the persistent discrepancy between PNLF and surface brightness fluctuation (SBF) distances. By adjusting the range of minimum to maximum final mass, it is also possible to explain the observed variety of PNLF shapes at intermediate magnitudes. The new PN formation rates are calculated to be slightly lower than suggested by previous simulations based on older post-AGB evolutionary tracks.