  A sample of 97 galactic field Be stars were studied by taking into account
the effects induced by the fast rotation on their fundamental parameters. All
program stars were observed in the BCD spectrophotometric system in order to
minimize the perturbations produced by the circumstellar environment on the
spectral photospheric signatures. This is one of the first attempts at
determining stellar masses and ages by simultaneously using model atmospheres
and evolutionary tracks, both calculated for rotating objects. The stellar ages
($\tau$) normalized to the respective inferred time that each rotating star can
spend in the main sequence phase ($\tau\_{\rm MS}$) reveal a mass-dependent
trend. This trend shows that: a) there are Be stars spread over the whole
interval $0 \la \tau/\tau\_{\rm MS} \la 1$ of the main sequence evolutionary
phase; b) the distribution of points in the ($\tau/\tau\_{\rm
MS},M/M\_{\odot}$) diagram indicates that in massive stars ($M \ga
12M\_{\odot}$) the Be phenomenon is present at smaller $\tau/\tau\_{\rm MS}$
age ratios than for less massive stars ($M \la 12M\_{\odot}$). This
distribution can be due to: $i$) higher mass-loss rates in massive objets,
which can act to reduce the surface fast rotation; $ii$) circulation time
scales to transport angular momentum from the core to the surface, which are
longer the lower the stellar mass.
