- Table 1:
Log of the observations.
ID is taken from Marconi et al. (1997) for NGC 2506, from Bruntt et al. (1999)
for NGC 6134, and from Lindoff (1972) for IC 4651.
is the identification number used in the BDA (Mermilliod 1995).
Coordinates are at J2000, and exposure time is in seconds.
F indicates FEROS spectra,
and U indicates UVES spectra. The P values given for the stars
in NGC 2506 are membership probabilities.
- Table 2:
Data for the observed stars in NGC 2506, NGC 6134, and IC 4651. V,
B-V are: CCD magnitudes from Marconi et al. (1997) for NGC 2506; photoelectric
measurements from Clariá & Mermilliod (1992) for NGC 6134; photoelectric
measurements from Eggen (1971), Lindoff (1972), and Jennens & Helfer (1975),
as reported in the BDA, for IC 4651. K is taken from 2MASS (Cutri et al. 2003).
Stromgren y, b-y are: from Bruntt et al. (1999) for NGC 6134, and
Anthony-Twarog & Twarog (2000) for IC 4651. S/N has been measured at about 670 nm. Radial velocities (Col. 8, in km s-1), are heliocentric.
- Table 3:
Adopted atmospheric parameters and derived Iron abundances
for observed stars in NGC 2506, NGC 6134, and IC 4651; n indicated the number of
lines retained in the analysis.
In the last column we give for comparison the value of gravity derived from
- Table 4:
Sensitivities of abundance ratios to errors in the atmospheric
parameters and in the equivalent widths.
- Table 5:
Values for the reddening as determined in the present paper;
the three E(B-V) values for each cluster derived from individual colours,
i.e. from (B-V), (b-y), and (V-K) respectively, are also given.
The last line gives the adopted reddening.
- Table 6:
Literature values for E(B-V) and E(b-y).
SFD98 = Schlegel et al. (1998); M+97 = Marconi et al. (1997); K+01 = Kim et al. (2001);
D+02 = Dias et al. (2002) (catalogue); KF91 = Kjeldsen & Frandsen (1991);
CM92 = Clariá & Mermilliod (1992); B+99 = Bruntt et al. (1999); AT+88 = Anthony-Twarog
et al. (1988); ATT00 = Anthony-Twarog & Twarog (2000); M+02 = Meibom et al. (2002).
- Table 7:
Comparison between Fe I abundances from spectrum synthesis and analysis for observed stars in NGC 2506, NGC 6134, and IC 4651.
- Table 8:
Literature values for metallicity, and methods used. The two values
given for NGC 2506 by Marconi et al. correspond to the best reproductions of the
observed CMDs with synthetic ones based on the Padova tracks (Bressan et al.
1993) at Z=0.008 and 0.02; note that further unpublished analyses with
updated evolutionary tracks have shown that the solar solution should
be excluded. The two solutions for IC 4651 given by Anthony-Twarog
& Twarog correspond to two different calibrations of the intrinsic b-y colour