Related papers: No unique quadratic ephemeris for VW Cep
Two observational campaigns were carried out during the eclipses of EE Cep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depth and durations of the…
A short period eclipsing binary star CV Boo is tested for the possible existence of additional bodies in the system with a help of the light equation method. We use data on the moments of minima from the literature as well as from our…
We present a multi-band photometric analysis of CRTS J163819.6+03485, the first low mass ratio (LMR) contact binary system with a period under the contact binary (CB) period limit. The unprecedented combination of mass ratio and period…
We present the photometric results of the eclipsing cataclysmic variable (CV) WZ Sge near the period minimum ($P_{min}$). Eight new mid-eclipse times were determined and the orbital ephemeris was updated. Our result shows that the orbital…
The orbital period of V Sge is decreasing at a rate which increased from dP/dt=-(4.11\pm 0.33)\times 10^{-10} in 1962 to -(5.44\pm 0.61)\times 10^{-10} in 2022. This implies that the mass trahsfer from the secondary component is…
We report on a new method for tracking the phases of the orbital modulations in very short-period, near-contact, and contact binary systems systems in order to follow starspots. We apply this technique to Kepler light curves for 414 binary…
We investigate the exchange of mass in a binary system as a channel through which a Be star can receive a rapid rotation. The mass-transfer phase in a massive close binary system in the Hertzsprung-gap is accompanied by the spinning up of…
We present 31 bright eclipsing contact and semi-detached binaries that showed high period change rates in a 5 year interval in observations by the All-Sky Automated Survey (ASAS). The time-scales of these changes range from only 50 up to…
We present our multicolour photometric data of the primary and secondary eclipses of OW Gem that took place in 1995, 2002, and 2006, as well as the new radial-velocity data collected since 1993 by R. F. Griffin and A. Duquennoy. The…
Aims. We present an in-depth study of the two components of the binary system LZCep in order to constrain the effects of binarity on the evolution of massive stars. Methods. We use a set of high-resolution, high signal-to-noise ratio…
Contact binary systems (also known as W UMa systems) consist of a pair of hydrogen-burning dwarf stars orbiting each other so closely that they share a common envelope. Although they are relatively common, there is as yet no established…
Context. Period variations have been detected in a number of eclipsing close compact binary subdwarf B stars (sdBs) and these have often been interpreted as caused by circumbinary massive planets or brown dwarfs. Various evolutionary…
Common-envelope evolution (CEE) is among the most uncertain phases in binary evolution. To empirically constrain CEE, we construct a uniformly selected sample of eclipsing post--common-envelope binaries (PCEBs). Starting from an unresolved…
A growing number of eclipsing binary systems of the "HW Vir" kind (i. e., composed by a subdwarf-B/O primary star and an M dwarf secondary) show variations in their orbital period, also called Eclipse Time Variations (ETVs). Their physical…
Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times…
The optical light of the symbiotic binary BF Cygni during its last eruption after 2006 shows orbital variations because of an eclipse of the outbursting compact object. The first orbital minimum is deeper than the following ones. Moreover,…
We report the discovery of 1RXH J082623.6-505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a $\sim 0.4 M_{\odot}$ K-type secondary transferring mass through a low-state…
This is our regular research in the field of cyclic O-C changes and third components. In this article the results of four new stars investigation is described. These stars are: BD And, SV Cam, V0836 Cyg and XZ CMi. All of them have cyclic…
We report a long-term (1961-2017) study of the eclipse times in the dwarf nova WZ Sagittae, in an effort to learn its rate of orbital-period change. Some wiggles with a time scale of 20-50 years are apparent, and a connection with the…
CW Cep is an early B-type eclipsing binary with mass measurement precisions better than 1 \%. We report the discovery of pulsation signatures in the TESS time-series data of the system observed during Sectors 17 and 18. Our binary modeling…