Related papers: Long-term investigation of an open cluster Berkele…
M giants are among the longest-period pulsating stars which is why their studies were traditionally restricted to analyses of low-precision visual observations, and more recently, accurate ground-based data. Here we present an overview of M…
A comprehensive census of Galactic open cluster properties places unique constraints on the Galactic disc structure and evolution. In this framework we investigate the evolutionary status of three poorly-studied open clusters, Berkeley 31,…
Open clusters serve as a useful tool for calibrating models of the relationship between mass, rotation, and age for stars with an outer convection zone due to the homogeneity of the stars within the cluster. Cluster to cluster comparisons…
In this paper we present time series photometry of 104 variable stars in the cluster region NGC 1893. The association of the present variable candidates to the cluster NGC 1893 has been determined by using $(U-B)/(B-V)$ and $(J-H)/(H-K)$…
We report astrophysical properties of 12 Milky Way open clusters located beyond the circle around the Sun where the number of catalogued open clusters is thought to be statistically complete. By using deep optical photometry, we estimated…
KIC 7177553 is a quadruple system containing two binaries of orbital periods 16.5 and 18 d. All components have comparable masses and are slowly rotating, non-evolved stars of spectral type near G2V. The longer period binary is eclipsing…
We present results of a BVI variability survey in the young open cluster NGC 457 based on observations obtained during three separate runs spanning almost 20 years. In total, we found 79 variable stars, of which 66 are new. The BVI…
This paper presents the detection of a periodic dimming event in the lightcurve of the G1.5IV-V type star KIC 1718360. This is based on visible-light observations conducted by both the TESS and Kepler space telescopes. Analysis of the data…
We have searched the Kepler light curves of ~3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms,…
We have obtained CCD UBVI_{KC} photometry down to V ~ 21.0 for the open clusters Berkeley 26, Czernik 27, Melotte 72, NGC 2479 and BH 37. The latter has never been studied before. Cluster stellar density profiles were obtained from star…
Over two dozen early F-type variable stars have been identified which constitute a new class of pulsating stars. These stars typically have periods between 0.5 and 3 days with V-band variability of several hundredths of a magnitude. Given…
The field of the globular cluster NGC 3201 was monitored between 1998 and 2009 in a search for variable stars. $BV$ light curves were obtained for 152 periodic or likely periodic variables, 57 of which are new detections. Thirty-seven newly…
Accurate measurements of young stellar cluster internal dynamics provide crucial insights into their formation. With Gaia, we are now able to trace stellar motions and study the dynamics of star clusters with unprecedented precision, but…
Photometric UBVI CCD photometry is presented for NGC 188 and Berkeley 17. Color-magnitude diagrams (CMDs) are constructed and reach well past the main-sequence turn-off for both clusters. Cluster ages are determined by means of isochrone…
We have obtained BVI CCD imaging of Berkeley 17, an anticentre open cluster that competes with NGC 6791 as the oldest known open cluster. Using the synthetic colour magnitude diagrams (CMD) technique with three sets of evolutionary tracks…
This study continues our investigation of early-type binaries using high-precision broad-band polarimetry, focusing on HD 165052, a massive O+O-type binary in the young cluster NGC 6530. Our aim was to monitor linear polarization variations…
Analysis of the longterm photometric variability of 7 Be/X-ray-pulsar systems in the Small Magellanic Cloud has been carried out. We find a variety of types of variability are present, including: longterm irregular changes, periodic orbital…
We present a kinematic and dynamical analysis of six Galactic open clusters NGC~2204, NGC~2660, NGC~2262, Czernik~32, Pismis~18, and NGC~2437, using \textit{Gaia}~DR3. We used Bayesian and Gaussian Mixture Model (GMM) methods to identify…
Our goal is to determine the rotational and magnetic-related activity properties of stars at different stages of evolution. We have focussed our attention on 6 young loose stellar associations within 100 pc and ages in the range 8-70 Myr:…
A comparison between the oscillation frequencies of six multi-periodic Delta Scuti stars of the Pleiades cluster and the eigenfrequencies of rotating stellar models that match the corresponding stellar parameters has been carried out. The…