Planetary nebulae in the direction of the Galactic bulge: On nebulae with emission-line central stars

TL;DR

This study provides homogeneous spectroscopic data for 90 Galactic bulge planetary nebulae, analyzing their plasma parameters, chemical abundances, and the properties of their emission-line central stars, revealing insights into their evolutionary stages.

Contribution

It offers the first detailed plasma and abundance measurements for half of the sample and classifies emission-line central stars, highlighting their evolutionary relationships.

Findings

WEL, VL, and [WR] central stars represent distinct evolutionary paths.

[WR] PNe are generally brighter than other PNe.

Chemical compositions of emission-line central star PNe are similar to other bulge PNe.

Abstract

We present a homogeneous set of spectroscopic measurements secured with 4-meter class telescopes for a sample of 90 planetary nebulae (PNe) located in the direction of the Galactic bulge. We derive their plasma parameters and chemical abundances. For half of the objects this is done for the first time. We discuss the accuracy of these data and compare it with other recently published samples. We analyze various properties of PNe with emission-line central stars in the Galactic bulge. Investigating the spectra we found that 7 of those PNe are ionized by Wolf-Rayet ([WR]) type stars of the very late (VL) spectral class [WC 11] and 8 by weak emission-line (WEL) stars. From the analysis we conclude that the PN central stars of WEL, VL and remaining [WR] types form three, evolutionary unconnected forms of enhanced mass-loss among central stars of PNe. [WR] PNe seem to be intrinsically brighter than other PNe. Overall, we find no statistically significant evidence that the chemical composition of PNe with emission-line central stars is different from that of the remaining Galactic bulge PNe.