Related papers: Close binary stars in the solar-age Galactic open …
We present CCD UBVI photometry of the nearby, intermediate age open cluster NGC 6939. Using the synthetic Colour - Magnitude Diagrams technique we estimate the following parameters: age between 1.3 and 1.0 Gyr (depending on whether or not…
We present an analysis of a slightly eccentric ($e=0.05$), partially eclipsing long-period ($P = 69.73$ d) main sequence binary system (WOCS 12009, Sanders 1247) in the benchmark old open cluster M67. Using Kepler K2 and ground-based…
CCD photometry on the intermediate-band uvbyCaH-beta system is presented for the old open cluster, NGC 6253. Despite a high level of field star contamination due to its location toward the galactic center, combination of the data from the…
We present a new study of late-type eclipsing binary stars in the Small Magellanic Cloud (SMC) undertaken with the aim of improving the distance determination to this important galaxy. A sample of 10 new detached, double-lined eclipsing…
Determining the distance to the open cluster M29 (NGC 6913) has proven difficult, with distances determined by various authors differing by a factor of two or more. To solve this problem, we have initiated a new photometric investigation of…
NGC 7789 is an intermediate-age open cluster with an age that is similar to the mean age of contact binary stars. V12 is a bright UMa-type binary star with an orbital period of 0.397 day. The first complete light curves of V12 in V, R, and…
The $13.6\times 13.6$ arcmin$^{2}$ field covering the central part of the globular cluster NGC~6397 was surveyed in a search for short-period variable stars. We obtained light curves for 6 close binaries, 2 SX~Phe stars and 1 RR~Lyrae…
We present UBVI photometry of the old open cluster NGC 1193. Color-magnitude diagrams (CMDs) of this cluster show a well defined main sequence and a sparse red giant branch. For the inner region of r<50 arcsec, three blue straggler…
We present observations and analysis of an RS CVn-type double-lined eclipsing binary system, RU Cnc. The system has been observed for over a century. The high-quality long-cadence \emph{Kepler} K2 C5 and C18, newly obtained observations,…
The discovery of true solar analogues is fundamental for a better understanding of the Sun and of the solar system. The open cluster M67 offers a unique opportunity to search for solar analogues because its chemical composition and age are…
Photometric observations in the R and I bands of the detached M-type double-lined eclipsing binary CU Cnc have been acquired and analysed. The photometric elements obtained from the analysis of the light curves have been combined with an…
We describe a variability study of the moderately old open cluster NGC 6819. We have detected 4 new detached eclipsing binaries near the cluster turnoff (one of which may be in a triple system). Several of these systems should be able to…
Detached eclipsing double line spectroscopic binaries are accurate distance indicators. They can be used for the direct determination of distances to globular clusters in which such systems can be identified. The results of major…
We present the results of BV(RI)_KC CCD photometry down to V=21 mag in the region of NGC 6994. To our knowledge, no photometry has previously been reported for this object and we find evidences that it is a poor and sparse old open cluster,…
Dynamical interactions in binary systems are thought to play a major role in the formation of extreme horizontal branch stars (EHBs) in the Galactic field. However, it is still unclear if the same mechanisms are at work in globular…
We have conducted a deep ($15 \la r \la 23$), 20 night survey for transiting planets in the intermediate age ($\sim 550 {\rm Myr}$) open cluster M37 (NGC 2099) using the Megacam wide-field mosaic CCD camera on the 6.5m Multiple Mirror…
We present a photometric and spectroscopic study of the blue straggler S1082 in the open cluster M67. Our observations confirm the previously reported 1.07 day eclipse light curve and the absence of large radial-velocity variations of the…
Five fields located close to the center of the globular cluster NGC 104=47 Tuc were surveyed in a search for variable stars. We present V-band light curves for 42 variables. This sample includes 13 RR Lyr stars -- 12 of them belong to the…
We report on deep (V $\approx$ 24.0) $VI$ CCD photometry of 3 fields centered in the regions of the old open clusters Saurer A, B and C. In the case of Saurer A, which is considered one of the oldest known open cluster, we also provide a…
We report on the discovery and analysis of short-period (0.1 days $< P <$ 5 days), photometrically varying binary stars around and below the main-sequence turnoff of the globular clusters (GCs) NGC 3201, M10, & M12. These eclipsing binaries…