Related papers: Cyclic Period Changes in Close Binaries: A Light T…
We searched the orbital period changes in 182 EA-type (including the 101 Algol systems used by \cite{hal89}), 43 EB-type and 53 EW-type binaries with known both the mass ratio and the spectral type of their secondary components. We…
Years to decade-long cyclic orbital period changes have been observed in several classes of close binary systems including Algols, W Ursae Majoris and RS Canum Venaticorum systems, and the cataclysmic variables. The origin of these changes…
Six semi-detached Algol-type binaries lacking a period analysis were chosen to test for a presence of a third body. The O-C diagrams of these binaries were analyzed with the least-squares method by using all available times of minima. Also…
We introduce a new model to explain the modulation of the orbital period observed in close stellar binary systems based on an angular momentum exchange between the spin of the active component and the orbital motion. This spin-orbit…
The existence of an additional body around a binary system can be detected by the help of the light-travel time effect. Due to the motions of binary and the companion stars around the common mass center of the ternary system, the light-time…
Orbital period changes of binary stars may be caused by the presence of a third massive body in the system. Here we have searched the archive of the Wide Angle Search for Planets (SuperWASP) project for evidence of period variations in…
This paper reviews the rich corpus of observational evidence for tidal effects in short-period binaries. We review the evidence for ellipsoidal variability and for the observational manifestation of apsidal motion in eclipsing binaries.…
The period changes of six eclipsing binaries have been studied with focus on the light-time effect. With the least squares method we also calculated parameters of such an effect and properties of the unresolved body in these systems. With…
The period changes of contact binaries obtained by the analysis of eclipse minima timing are found mostly chaotic in nature. However, they are representable by a few cyclic changes superposed on a secular change. The cyclic changes are…
Tidal forces in close binary systems have diverse impacts on magnetic activity. The synchronicity characteristic of close systems counteracts magnetic braking, thereby sustaining rapid rotation-a key factor in increased levels of magnetic…
Analyzing the available photometry from the Kepler satellite and other databases, we performed detailed light curve modeling of 10 eclipsing binary systems that were found to exhibit a periodic modulation of their orbital periods. All of…
It is generally thought that conservative mass transfer in Algol binaries causes their orbits to be wider, in which the less massive star overflows its Roche-lobe. The observed decrease in the orbital periods of some Algol binaries suggests…
Two Algol-type eclipsing binary systems (EW Lyr and IV Cas) have been investigated for period changes. Our study was primarily focused on the light-time effect with an alternative explanation by magnetic activity cycles. In the case of EW…
Four eclipsing binaries, which show apparent changes of period, have been studied with respect to a possible presence of the light time effect. With a least squares method we calculated new light elements of these systems, the mass function…
We report the results of a statistical study of cyclical period changes in cataclysmic variables (CVs). Assuming the third-body hypothesis as the cause of period changes, we estimate the third-body mass, $m_3$, and its separation from the…
We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, both detached and semi-detached and…
The evolution of contact binary star systems in mass asymmetry (transfer) coordinate is considered. The orbital period changes is explained by an evolution in mass asymmetry towards the symmetry (symmetrization of binary system). It is…
Magnetic braking causes the spin-down of single stars as they evolve on the main sequence. Models of magnetic braking can also explain the evolution of close binary systems, including cataclysmic variables. The well-known period gap in the…
We present here results of numerical calculations demonstrating that the very long periodic variability detected in the Cataclysmic Variable FS Aur can be the result of eccentricity modulation of a close binary (CB) orbit induced by the…
During the motion of a binary pulsar around the Galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a…