  The present work is devoted to the study of faint Be stars observed by CoRoT
in the fourth long run (LRA02). The astrophysical parameters were determined
from the spectra observed with the VLT/FLAMES instruments at ESO. Spectra were
fitted with models of stellar atmospheres using our GIRFIT package. Spectra in
the lambda-lambda 6400-7200$ AA domain enabled the confirmation or a first
identification of Be star candidates. The apparent parameters (Teff,log g,Vsin
i) for a set of 19 B and Be stars were corrected for the effects induced by the
rapid rotation. These allowed us to determine: 1) masses that are in agreement
with those measured for detached binary systems; 2) distances that agree with
the GAIA parallaxes; and 3) centrifugal/gravity equatorial force ratios of
~0.6-0.7, which indicate that our Be stars are subcritical rotators. A study of
the Balmer Halpha, Hgamma and Hdelta emission lines produced: extents of the
circumstellar disk (CD) emitting regions that agree with the interferometric
inferences in other Be stars; R-dependent exponents n(R) of the CD radial
density distributions; CD base densities. The Hgamma and Hdelta emission lines
are formed in CD layers close to the central star. These lines produced a
different value of the exponent n(R) than assumed for Halpha. Further detailed
studies of Hgamma and Hdelta emission lines could reveal the physical
properties of regions where the viscous transport of angular momentum to the
remaining CD regions is likely to originate from. The subcritical rotation of
Be stars suggests that their huge discrete mass-ejections and concomitant
non-radial pulsations might have a common origin in stellar envelope regions
that become unstable to convection due to rotation. The errors induced on the
estimated Teff by the possible presence of stripped sub-dwarf O/B companions
are not likely to exceed their present uncertainties.
