Open cluster survival within the solar circle: Teutsch145 and Teutsch146
  Teutsch145 and Teutsch146 are shown to be open clusters (OCs) orbiting well
inside the Solar circle, a region where several dynamical processes combine to
disrupt most OCs on a time-scale of a few 10^8yrs. BVI photometry from the
GALILEO telescope is used to investigate the nature and derive the fundamental
and structural parameters of the optically faint and poorly-known OCs
Teutsch145 and 146. These parameters are computed by means of field-star
decontaminated colour-magnitude diagrams (CMDs) and stellar radial density
profiles (RDPs). Cluster mass estimates are made based on the intrinsic mass
functions (MFs). We derive the ages 200+100-50Myr and 400+/-100Myr, and the
distances from the Sun 2.7+/-0.3kpc and 3.8+/-0.2kpc, respectively for
Teutsch145 and 146. Their integrated apparent and absolute magnitudes are m_V ~
12.4, m_V ~ 13.3, M_V ~- 5.6 and M_V ~- 5.3. The MFs (detected for stars with
m>1Msun) have slopes similar to Salpeter's IMF. Extrapolated to the H-burning
limit, the MFs would produce total stellar masses of ~1400Msun, typical of
relatively massive OCs. Both OCs are located deep into the inner Galaxy and
close to the Crux-Scutum arm. Since cluster-disruption processes are important,
their primordial masses must have been higher than the present-day values. The
conspicuous stellar density excess observed in the innermost bin of both RDPs
might reflect the dynamical effects induced by a few 10^8yrs of external tidal
stress.
