Planetary nebulae and the chemical evolution of the galactic bulge: new abundances of older objects

TL;DR

This study presents new chemical abundance data for older planetary nebulae in the galactic bulge, revealing lower abundances and a different gradient trend, supporting recent galactic chemical evolution models.

Contribution

It provides the first detailed abundances for faint, older planetary nebulae in the galactic bulge, extending previous datasets and testing chemical evolution models.

Findings

Lower abundances in older bulge PNe compared to previous data.

Bulge PNe do not follow the disk's radial abundance gradient.

Results support recent galactic chemical evolution models.

Abstract

In view of their nature, planetary nebulae have very short lifetimes, and the chemical abundances derived so far have a natural bias favoring younger objects. In this work, we report physical parameters and abundances for a sample of old PNe located in the galactic bulge, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman Spectrograph. The new data allow us to extend our database including older, weaker objects that are at the faint end of the planetary nebula luminosity function (PNLF). The results show that the abundances of our sample are lower than those from our previous work. Additionally, the average abundances of the galactic bulge do not follow the observed trend of the radial abundance gradient in the disk. These results are in agreement with a chemical evolution model for the Galaxy recently developed by our group.