Observations of Planetary Nebulae in the Galactic Bulge
F.Cuisinier, W.J.Maciel, A.Acker, J.Köppen, B.Stenholm
ABSTRACT High quality spectrophotometric observations of 30 Planetary Nebulae in the Galactic Bulge have been made. Accurate reddenings, plasma parameters, and abundances of He, O, N, S, Ar, Cl are derived.
We find the abundances of O, S, Ar in the Planetary Nebulae in the Galactic Bulge to be comparable with the abundances of the Planetary Nebulae in the Disk, high abundances being maybe slightly more frequent in the Bulge.
The distribution of the N/O ratio does not present in the Galactic Bulge Planetary Nebulae the extension to high values that it presents in the Disk Planetary Nebulae. We interpret this as a signature of the greater age of Bulge Planetary Nebulae.
We thus find the Bulge Planetary Nebulae to be an old population, slightly more metal-rich than the Disk Planetary Nebulae. The population of the Bulge Planetary Nebulae shows hence the same characteristics than the Bulge stellar population.