| Abstract | dc.description.abstract | We present optical and infrared photometry for VdB-Hagen 67, an overlooked old open cluster
located at l = 273.◦76, b = −0.◦375 (RA 09h26m45s, Dec.−51◦16 00 , J2000.0) in the fourth
Galactic quadrant, in the direction of theVela Molecular Ridge. VdB-Hagen 67 is immersed in a
dense stellar field which is characterized by highly patchy extinction, andAV in the line of sight
to the cluster is larger than 3mag. The cluster looks symmetric and it clearly stands out from
the general Galactic field. By means of a star count analysis, both in the optical and IR, we have
estimated that its radius is of about 2 arcmin. Before this study, only very general information
was available for this cluster, but here we have determined its fundamental parameters. The
age of VdB-Hagen 67 has been estimated, both empirically and with theoretical isochrones,
and turns out to be about 1.3 Gyr. The difficulty to separate cluster members from interlopers
prevented us from estimating its metallicity. No traces of subgiant or red-giant branch stars are
visible in its field-star-decontaminated colour–magnitude diagrams; VdB-Hagen 67 is an old,
poorly populated, star cluster on the verge of dissolving into the general Galactic field. We
derive a heliocentric distance of ∼7.5 kpc and a galactocentric distance of ∼11.5 kpc. With
the exception of FSR 1415 at 8.6 kpc, and with an age of ∼2.5Gyr , no other old clusters are
known so far from the Sun in this Galactic sector. We argue that in this region of the Galactic
plane several other distant clusters of this age have to exist, but have not been unravelled
mainly because of the significant extinction produced by the dense Vela Molecular Ridge. | en_US |
