PLANETARY NEBULAE AND THE CHEMICAL EVOLUTION OF THE GALACTIC BULGE:
NEW ABUNDANCES OF OLDER OBJECTS
O. Cavichia, R. D. D. Costa, M. Mollá, W. J. Maciel
IAU Symposium No. 283, Ed. A. Manchado, L. Stanghellini, D. Schönberner, 326-327
(2012)
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.
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