174 citations · 227 across the 3 of their papers we have counts for
3 papers
astro-ph2006★ 174 cited
A Possible Origin of the Mass-Metallicity Relation of Galaxies
J. Koeppen, C. Weidner, P. Kroupa
Observations show that galaxies follow a mass-metallicity relation over a wide range of masses. One currently favoured explanation is that less massive galaxies are less able to re…
astro-ph2006★ 53 cited
Chemical compositions and plasma parameters of planetary nebulae with Wolf-Rayet and wels type central stars
P. Girard, J. Koppen, A. Acker
Aims: Chemical compositions and other properties of planetary nebulae around central stars of spectral types [WC], [WO], and wels are compared with those of `normal' central stars,…
astro-ph2001
The Galactic Bulge: The Stellar and Planetary Nebulae Populations
F. Cuisinier, J. Koppen, A. Acker +1
We compare abundances patterns in the Bulge for elements observed in stars and in planetary nebulae. Some alpha elements, like Mg and Ti, are overabundant respect to Fe, and others…