Planetary nebulae, tracers of stellar nucleosynthesis

TL;DR

This paper reviews how planetary nebulae and their progenitors serve as tools to study stellar nucleosynthesis and mixing in low and intermediate mass stars, highlighting new spectroscopic methods and current challenges.

Contribution

It introduces new high signal-to-noise spectroscopic approaches for analyzing planetary nebulae and discusses limitations in using them to trace original oxygen abundances in low metallicity environments.

Findings

High-quality spectroscopy enhances understanding of stellar processes.

Planetary nebulae in low metallicity environments do not reliably indicate original oxygen levels.

Challenges remain in disentangling stellar evolution effects from observed abundances.

Abstract

We review the information that planetary nebulae and their immediate progenitors, the post-AGB objects, can provide to probe the nucleosynthesis and mixing in low and intermediate mass stars. We emphasize new approaches based on high signal-to-noise spectroscopy of planetary nebulae and of their central stars. We mention some of the problems still to overcome. We emphasize that, as found by several authors, planetary nebulae in low metallicity environments cannot be used to probe the oxygen abundance in the interstellar medium out of which their progenitors were formed, because of abundance modification during stellar evolution.