The Hipparcos catalogue provides an
accurate and extensive sampling of the solar
neighbourhood HR diagram. The morphology of this
diagram depends on selection criteria of the
catalogue such as the limiting magnitude, angular
separation and on the characteristics of the
stellar populations near the sun (space density,
metallicity, star formation rate, etc). Since the
Hipparcos data are so accurate, one needs to model
precisely the different selection bias and, at the
same time, parametrize models of the galactic
stellar populations with sufficient flexibility
that as much information as possible can be
grasped from the catalogue.
Comparisons between our model and the
Hipparcos catalogue will be presented elsewhere.
Since the quantity of information contained in the
Hipparcoscatalogue is so important, models ought
to be complex, and external contraints, obtained
prior to any general comparison with the model,
are welcome.
A major factor that influences the
distribution of the stars in the HR diagram is the
metallicity. For the late type stars, the
metallicity distribution can be best studied by
re-analysing a volume-limited sample of stars from
the catalogue.
The Metallicity Distribution of Late Type
Dwarfs
