Towards a comprehensive knowledge of the open cluster Haffner 9
  We turn our attention to Haffner 9, a Milky Way open cluster whose previous
fundamental parameter estimates are far from being in agreement. In order to
provide with accurate estimates we present high-quality Washington CT1 and
Johnson BVI photometry of the cluster field. We put particular care in
statistically clean the colour-magnitude diagrams (CMDs) from field star
contamination, which was found a common source in previous works for the
discordant fundamental parameter estimates. The resulting cluster CMD fiducial
features were confirmed from a proper motion membership analysis. Haffner 9 is
a moderately young object (age ~ 350 Myr), placed in the Perseus arm -at a
heliocentric distance of ~ 3.2 kpc-, with a lower limit for its present mass of
~ 160 Mo and of nearly metal solar content. The combination of the cluster
structural and fundamental parameters suggest that it is in an advanced stage
of internal dynamical evolution, possibly in the phase typical of those with
mass segregation in their core regions. However, the cluster still keeps its
mass function close to that of the Salpeter's law.
