Improving the determination of chemical abundances in planetary nebulae

TL;DR

This paper improves the accuracy of chemical abundance determinations in planetary nebulae by incorporating new emissivities and ionization correction factors, refining elemental abundance measurements and addressing the sulphur anomaly.

Contribution

It introduces a new code using recent emissivities and ICFs to re-evaluate and determine more accurate chemical abundances in planetary nebulae.

Findings

S abundances are higher than previous estimates.

New ICFs help partially resolve the sulphur anomaly.

Elemental abundances of He, N, O, Ar, and Ne are slightly modified.

Abstract

Planetary nebulae are the products of the evolution of low and intermediate mass stars. The chemical property studies of these objects give important information about the elemental abundances as He, O, Ne, Ar, S and their modifications associated with the evolution of the progenitor stars. The determination of accurate abundances in planetary nebulae is important from the perspective of the stellar evolution as well as the formation and chemical evolution of galaxies. Recently, new HeI emissivities and ionization correction factors (ICFs) were published in the literature. In this work, these new parameters are used in a code for the determination of chemical abundances in photoionized nebulae. This code is used for the recompilation of the chemical abundances of planetary nebulae from the Galactic bulge observed previously by our group and also for the determination of new chemical abundances of a sample of planetary nebulae located near the Galactic centre. The new emissivities and ICFs slightly modified the elemental abundances of He, N, O, Ar and Ne. On the other hand, S abundances are higher than previous determinations. The new ICFs can contribute to solve partially the sulphur anomaly.