  The application of the Stromgren photometric luminosity calibrations to
different types of CP stars is reexamined in the light of the new Hipparcos
data. A first attempt is made to use the LM statistical parallax method (Luri
et al., 1996) -- based on the maximum likelihood principle -- to obtain a
calibration of the absolute magnitude as a function of two Stromgren colour
indices, thus reflecting effective temperature and evolution. Its application
to a sample of Si stars and to a sample of normal main sequence stars in the
same spectral range allows us to compare the calibrations obtained and to
discuss the position of Si stars in the HR diagram. Additionally, a sample of
bonafide, spectroscopically selected Am stars together with normal main
sequence stars are used to derive a new absolute magnitude calibration for late
A-type main sequence stars, taking into account the effects of evolution,
metallicity and stellar rotation.
