Several evolutionary channels for bright planetary nebulae

TL;DR

This paper explores different evolutionary pathways for bright planetary nebulae, highlighting their spectral differences across galaxy types and suggesting a secular evolution origin for the Milky Way's bulge.

Contribution

It proposes multiple evolutionary channels for bright planetary nebulae and links the Milky Way bulge's properties to those of spiral discs.

Findings

Bright planetary nebulae in spiral discs and ellipticals differ spectrally.

Milky Way bulge planetary nebulae are similar to those in spiral discs.

The Milky Way bulge may have evolved from the disc, acting as a pseudo-bulge.

Abstract

The populations of bright planetary nebulae in the discs of spirals appear to differ in their spectral properties from those in ellipticals and the bulges of spirals. The bright planetary nebulae from the bulge of the Milky Way are entirely compatible with those observed in the discs of spiral galaxies. The similarity might be explained if the bulge of the Milky Way evolved secularly from the disc, in which case the bulge should be regarded as a pseudo-bulge.