Related papers: Variable stars in the Open Cluster M11 (NGC 6705)
We present the results of a photometric survey for variable stars in the central region of the nearby globular cluster NGC 6397.Time series photometry was obtained for 30 variable objects. The sample includes 12 new objects, of which 6 show…
We present a catalog of photometrically variable stars discovered within two 21'.3 X 21'.3 fields centered on the Cygnus OB2 association. There have hitherto been no deep optical variability studies of Cyg OB2 despite it being replete with…
We present preliminary results obtained from analysis of the VI photometry of the globular cluster M79. Stellar variability survey performed with the image subtraction method yielded six new pulsating stars: two of RR Lyrae type, three SX…
We report on the discovery of eleven multimode SX Phoenicis--type blue stragglers in the field of the southern globular cluster NGC 3201. In these variables both radial and non-radial modes are excited. For three variables the derived…
We present results of a spectroscopic study of 37 southern (candidate) gamma Doradus stars based on echelle spectra. The observed spectra were cross-correlated with the standard template spectrum of an F0-type star for an easier detection…
We present results of multi-epoch (fourteen nights during 2007-2010) $V$-band photometry of the cluster NGC 1893 region to identify photometric variable stars in the cluster. The study identified a total of 53 stars showing photometric…
We present an analysis of \emph{VI} CCD time-series photometry of the Oo II type globular cluster M92. The variable star population of the cluster is studied with the aim of revising their classifications, identifications, frequency spectra…
The results of a CCD survey for variability of stars in the nearby galaxy NGC 6822 are presented. The goal of the survey was to obtain good light curves of Cepheids for Fourier decomposition and to detect shorter period Cepheids. Since the…
We have conducted a 1.5 year-long variability study of the stars in the Cygnus OB2 association, the region in the northern hemisphere with the highest density of optically visible massive stars. The survey was conducted using four pointings…
In a photometric variability survey of 131 stars with B < 14 mag, we have found four new Delta Scuti stars. We were sensitive to oscillation amplitudes as low as a few mmag. The detection rate of short-period (P < 0.1 d) pulsating variable…
We report results of VI time series photometry for the bright globular cluster M5 taken between 2007-2011 using the 0.5-m telescope at Bowling Green State Univ. and the PROMPT #4 telescope at Cerro Tololo. We used DAOPHOT to obtain…
Nine new short period variable stars have been discovered in the direction of the open cluster Cr464 in Camelopardalis. The field was observed using Tzec Maun Observatory's telescope AP180. Two new variable stars were classified as…
We present a variability study of 4646 massive stars in the Small Magellanic Cloud (SMC) with known spectral types from the catalog of Bonanos et al. (2010) using the light curves from the OGLE-III database. The goal is to exploit the time…
We have undertaken a long-term project, Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. As our first target we have chosen NGC 6791 -- a very old, populous, metal rich cluster. In…
We report CCD $V$ and $I$ time-series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05 mag for stars brighter than $V \sim 19.0$…
We report the results of CCD photometric observations in the direction of the Coma Berenices and Upgren 1 open clusters with the aim at searching for new short-period variable stars. A total of 35 stars were checked for variability. As a…
We have investigated 1008 objects in the area of five intermediate age open clusters (NGC 2099, NGC 3114, NGC 6204, NGC 6705 and NGC 6756) via the narrow band Delta a-system. The detection limit for photometric peculiarity is very low…
We report twelve variables not previously detected in the globular cluster M5 (NGC 5904); one SX Phe and eleven semi-regular variables (SR). Their identifications, equatorial coordinates, ephemerides, and light curves are given.…
Periodic variables are always of great scientific interest in astrophysics. Thanks to the rapid advancement of modern large-scale time-domain surveys, the number of reported variable stars has experienced substantial growth for several…
We report on the results of a long time photometric monitoring of the two metal poor Galactic globular clusters M22 and IC4499 searching for long period variables (LPVs) on the upper giant branch. We detected 22 new LPVs in the field of M22…