9 papers
On some Uncertainties in Evolutionary Synthesis Models
M. Cervino, D. Valls--Gabaud
Ranging from track interpolation techniques through model atmospheres to the stochastic nature of the IMF, there are many uncertainties which need to be taken into account when mod…
Metal abundance of the eclipsing binary YZ Cas: discrepancy between atmospheric determinations for the Am component
E. Lastennet, D. Valls-Gabaud, C. Jordi
We review current and new estimates of the eclipsing binary YZ Cassiopeiae metallicity (Z). Since the individual components cover a quite large range of mass (1.35-2.31 Solar masse…
Euler, Hipparcos and the five dwarfs : Reconstructing star formation histories in the Local Group
David Valls-Gabaud, Xavier Hernandez, Gerry Gilmore
The unprecedented quality of recent colour-magnitude diagrams of resolved stellar populations in nearby galaxies requires state-of-the-art techniques to infer the star formation hi…
Stringent constraints on single-star evolution theory from masses and radii of well-detached binaries in star clusters
E. Lastennet, D. Valls-Gabaud, E. Oblak
Which sample of objects can give strong constraints on single-star evolution theory ? Whilst star cluster members share the same age and the same metallicity, many questions (e.g.…
ROSAC: Studying the clustering properties of X-ray selected AGNs
F. Tesch, F. J. Carrera, D. Engels +6
We present the first ROSAC results of an AGN clustering analysis. This study comprises a sample of 200 AGNs, 75% of which being at low redshifts z<0.5, in the Ursa Major constellat…
Influence of Hipparcos on Hyades age estimates from three binary systems
E. Lastennet, D. Valls-Gabaud, T. Lejeune +1
Three independent sets of stellar theoretical models are tested with well-detached systems of the Hyades open cluster: 51 Tau, V818 Tau, and Tau. The choice of these objects…