# Stellar yields and abundances: new directions from planetary nebulae

## TL;DR

This paper discusses how planetary nebulae observations provide insights into nucleosynthesis, element abundances, and stellar evolution, especially regarding the s process and initial stellar mass inference.

## Contribution

It introduces new observational approaches to study nucleosynthesis signatures in planetary nebulae and their implications for stellar evolution models.

## Key findings

- Abundances of heavy elements like Kr and Xe inform s-process operation.
- Rb abundance in Type I planetary nebulae helps estimate initial stellar mass.
- Noble gases in meteoritic SiC grains relate to planetary nebulae wind environments.

## Abstract

Planetary nebulae retain the signature of the nucleosynthesis and mixing events that occurred during the previous AGB phase. Observational signatures complement observations of AGB and post-AGB stars and their binary companions. The abundances of the elements heavier than iron such as Kr and Xe in planetary nebulae can be used to complement abundances of Sr/Y/Zr and Ba/La/Ce in AGB stars, respectively, to determine the operation of the slow neutron-capture process (the s process) in AGB stars. Additionally, observations of the Rb abundance in Type I planetary nebulae may allow us to infer the initial mass of the central star. Several noble gas components present in meteoritic stardust silicon carbide (SiC) grains are associated with implantation into the dust grains in the high-energy environment connected to the fast winds from the central stars during the planetary nebulae phase.