- ... clusters
- Based on data collected at the European Southern
Observatory, Chile.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
- ... lines
- We only used H
.
H
was not
observed; the other members of the Balmer series were indeed observed, but
they are more contamined by metal lines, and their dependence on gravity,
metal abundance and details in the convection much larger than for H
(see Fuhrmann et al. 1993).
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
- ... subgiants
- The errors for
's we
quote for cluster stars are smaller than those we give for - individual -
field stars, in spite of the lower S/N values. This is because errors in
individual
's are due to the flat fielding, and are then only
marginally dependent on S/N; on the other side, temperatures for cluster stars
are obtained averaging over the values obtained for all similar stars: for
instance, in the case of NGC 6752 TO-stars, the adopted
is the
average of the values obtained for nine individual stars. Star-to-star scatter
in these
's is similar to the error bar we obtain for individual
field star.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.