9 papers
Chemical Composition of Planetary Nebulae: The Galaxy and the Magellanic Clouds
W. J. Maciel, R. D. D. Costa, T. E. P. Idiart
An analysis is made of the abundances of planetary nebulae (PN) in the Galaxy (MW), the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). The data has been gathere…
A comparison of the time variation of radial abundance gradients from planetary nebulae and open clusters
W. J. Maciel, R. D. D. Costa, P. A. L. Ferreira
The temporal behaviour of the radial abundance gradients has important consequences on models for the chemical evolution of the Galaxy. We present a comparison of the time variatio…
PN and galactic chemical evolution
W. J. Maciel, R. D. D. Costa
Recent applications of PN to the study of galactic chemical evolution are reviewed, such as PN and stellar populations, abundance gradients, including their space and time variatio…
Radial gradients and metallicities in the galactic disk
W. J. Maciel
Radial O/H abundance gradients derived from HII regions, hot stars and planetary nebulae are combined with [Fe/H] gradients from open cluster stars in order to derive an independen…
Stars and Planetary Nebulae in the Galactic Bulge
F. Cuisinier, J. Koppen, A. Acker +1
We compare the populations of Red Giant stars and Planetary Nebulae in the Galactic Bulge, in the light of recent determinations of their abundances patterns. We find both populati…
Some aspects of the chemical evolution of 4He in the Galaxy: the He/H abundance gradient and the Delta Y/Delta Z enrichment ratio
W. J. Maciel
Two aspects of the chemical evolution of 4He in the Galaxy are considered on the basis of a sample of disk planetary nebulae by the application of corrections due to the contaminat…