We derive fundamental , structural , and photometric parameters of 15 overlooked Ruprecht ( hereafter Ru ) star clusters by means of 2MASS photometry and field-star decontamination .
Ru 1 , 10 , 23 , 26 , 27 , 34 , 35 , 37 , 41 , 54 , 60 , 63 , 66 , and 152 are located in the third Galactic quadrant , while Ru 174 is in the first .
With the constraints imposed by the field-decontaminated colour-magnitude diagrams ( CMDs ) and stellar radial density profiles ( RDPs ) , we derive ages in the range 400 Myr — 1 Gyr , except for the older Ru 37 , with \sim 3 Gyr .
Distances from the Sun are within 1.5 \la \mbox { $d _ { \odot } $ } ( kpc ) \la 8.0 .
The RDPs are well-defined and can be described by a King-like profile for most of the radial range , except for Ru 23 , 27 , 41 , 63 , and 174 , which present a conspicuous stellar density excess in the central region .
The clusters dwell between ( or close to ) the Perseus and Sagittarius-Carina arms .
We derive evidence in favour of cluster size increasing with distance to the Galactic plane ( Z _ { GP } ) , which is consistent with a low frequency of tidal stress associated with high- | \mbox { $Z _ { GP } $ } | regions .
The clusters are rather faint even in the near-infrared , with apparent integrated J magnitudes within 6.4 \la m _ { J } \la 9.8 , while their absolute magnitudes are -6.6 \la M _ { J } \la - 2.6 .
Extrapolation of the relation between M _ { V } and M _ { J } , derived for globular clusters , suggests that they are low-luminosity optical clusters , with -5 \la M _ { V } \la - 1 .