On the physical reality of overlooked open clusters

A.E. PIATTI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 466 p. 4960 - 4973

0035-8711

We present  $UBVRI$ and $CT_1T_2$ photometry for fifteen catalogued open clustersof relative high brightness and compact appearance. From these unprecedentedphotometric data sets, covering wavelengths from the blue up to the near-infrared,we performed a thorough assessment of their reality as stellar aggregates.We statistically assignedto each observed star within the object region a probability of being a fiducial featureof that field in terms of its local luminosity function, colour distribution and stellar density. Likewise, we used accurate parallaxesand proper motions measured by the {it Gaia} satellite to help ourdecision on the open cluster reality. Ten catalogued aggregates did not show any hint of being real physical systems; three of them had been assumed tobe open clusters in previous studies, though. On the other hand, we estimated reliable fundamentalparameters for the remaining five studied objects, which were confirmed as realopen clusters. They resulted to be clusters distributed in a wide age range, 8.0 $le$ $log$($t$ yr$^{-1}$) $le$ 9.4, of solar metal content and placed between 2.0 and 5.5 kpcfrom the Sun. Their ages and metallicities are in agreement with the presently knownpicture of the spatial distribution of open clusters in the Galactic disc.