Related papers: Canis Major OB1 stellar groups contents revealed b…

We report here on the photometric and kinematic properties of a well defined group of nearly 200 low-mass pre-main sequence stars, concentrated within ~ 1 deg of the early-B star 25 Ori, in the Orion OB1a sub-association. We refer to this…

Recent studies indicate that some Galactic open clusters (OCs) exhibit extended main-sequence turnoff (eMSTO) in their colour-magnitude diagrams (CMDs). However, the number of Galactic OCs with eMSTO structures detected so far is limited,…

The formation mechanisms of open cluster (OCs) groups remain unclear due to limited sample sizes and data precision. Recent advancements in Gaia astrometric data provide an unprecedented opportunity to study OC groups in greater detail.…

We report the discovery of 25 new open clusters resulting from a search in dense low galactic latitude fields. We also provide, for the first time, structural and astrophysical parameters for the new findings and 34 other recently…

Context. Only a few open clusters are as important for the study of stellar and substellar objects, and their formation and evolution, as the young sigma Orionis cluster. However, a complete spectroscopic characterisation of its whole…

The Galactic globular cluster system is incomplete, especially in the low latitude regions of the Galactic bulge and disk. We report the physical characterization of twelve star clusters in the Milky Way, most of which are explored here for…

The kinematics of stars in OB associations can provide insights into their formation, dynamical evolution, and eventual fate. The low-mass stellar content of OB associations are sufficiently numerous as to provide a detailed sampling of…

Both star clusters and variable stars are sensitive laboratories of stellar astrophysics and evolution: cluster member stars provide context for interpreting cluster populations, whereas variability reveals the nature of individual stellar…

With the release of Gaia data, the number of known Galactic open clusters (OCs) has increased rapidly, providing an excellent opportunity to confirm more binary open clusters in the Milky Way. Using a recently released OC catalogue, we…

The Orion OB1a sub-association is a rich low mass star (LMS) region. Previous spectroscopic studies have confirmed 160 LMSs in the 25 Orionis stellar group (25 Ori), which is the most prominent overdensity of Orion OB1a. Nonetheless, the…

After leaving the main sequence, massive stars undergo complex evolution, still poorly understood. With a population of 100s OB stars, the starburst cluster Westerlund~1 offers an unparallelled environment to study their evolutionary…

We present a catalog of 2,990 extended sources in a 1deg x1deg area centered on M33 using the MegaCam camera on the 3.6m Canada-France-Hawaii telescope (CFHT). The catalog includes 599 new candidate stellar clusters, 204 previously…

We have identified stellar and substellar members in the nearby star cluster Coma Berenices, using photometry, proper motions, and distances of a combination of 2MASS, UKIDSS, URAT1, and {\it Gaia}/DR2 data. Those with {\it Gaia}/DR2…

The massive stellar content, the OB associations and the star clusters in an HST field in M101 = NGC 5457 are investigated. A clustering algorithm yields 79 putative associations. Their size distribution is similar to that found in the…

We present the preliminary results of an image-subtraction analysis of the Galactic globular cluster M79 (NGC 1904), as well as a new investigation of the variable star population in NGC 1851. Both M79 and NGC 1851 have been previously…

Stars form predominantly in groups which display a broad spectrum of masses, sizes, and other properties. Despite this diversity there exist an underlying structure that can constrain cluster formation theories. We show how combining…

The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than $\sigma_\pi/\pi\leq0.10$ and…

An understanding of the assembly history of the complex star cluster Omega Centauri has long been sought after, with many studies separating the stars on the color-magnitude diagram into multiple groupings across small magnitude ranges.…

The characterization of multiple stellar systems is an important ingredient for testing current star formation models. Stars are more often found in multiple systems, the more massive they are. A complete knowledge of the multiplicity of…

We present a catalogue of astrophysical data of 520 Galactic open clusters. These are the clusters, for which at least three most probable members (18 on average) could be identified in the ASCC-2.5, a catalogue of stars based on the…