Related papers: Dynamical evolution of active detached binaries on…
Evidence of secular dynamical evolution for detached active binary orbits are presented. First order decreasing rates of orbital angular momentum (OAM), systemic mass ($M=M_{1}+M_{2}$) and orbital period of detached active binaries have…
A set of 27 evolutionary models of cool close binaries was computed under the assumption that their evolution is influenced by the magnetized winds. Initial periods of 1.5, 2.0 and 2.5 d were considered. For each period three values of 1.3,…
A new scenario for evolution of contact binaries is presented and discussed. Arguments are given that W UMa-type systems are formed from detached binaries which lose angular momentum via magnetized wind. This takes typically several Gyr.…
Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each…
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…
The period histograms of eclipsing binaries generated with ASAS data cannot only be interpreted by orbital evolution. The eclipse probabilities, selection effects and space distributions in the solar neighborhood should be considered before…
Kinematics of 237 Chromospherically Active Binaries (CAB) were studied. The sample is heterogeneous with different orbits and physically different components from F to M spectral type main sequence stars to G and K giants and super giants.…
Well-determined physical parameters of 130 W UMa systems have been collected from the literature. Based on these data, the evolutionary status and dynamical evolution of W UMa systems are investigated. It is found that there is no…
Recently, our understanding of the origin of W UMa-type contact binaries has become clearer. Initial masses of their components were successfully estimated by Y{\i}ld{\i}z and Do\u{g}an using a new method mainly based on observational…
The kinematics of 129 W UMa binaries is studied and its implications on the contact binary evolution is discussed. The sample is found to be heterogeneous in the velocity space that kinematically younger and older contact binaries exist in…
The secular evolution of the orbital angular momentum (OAM), the systemic mass $(M=M_{1}+M_{2})$ and the orbital period of 114 chromospherically active binaries (CABs) were investigated after determining the kinematical ages of the…
Close detached binaries were theoretically predicted to evolve into contact by three subtypes of case A binary evolution: case AD, AR, and AS, which correspond to the formation of contact during dynamic-, thermal-, and nuclear-timescale…
Surveys of the binary populations in the solar neighbourhood have shown that the periods of G- and M-type stars are log-normally distributed. However, observations of young binary populations suggest a log-uniform distribution. Clearly some…
ASAS is a long term project to monitor bright variable stars over the whole sky. It has discovered 50,122 variables brighter than V < 14 mag south of declination +28 degrees, and among them 11,099 eclipsing binaries. We present a…
In a preceding paper, using Eggleton's evolution code we have discussed the structure and evolution of low-mass W UMa type contact binaries without angular momentum loss (AML). The models exhibit cyclic behavior about a state of marginal…
Theoretical study indicates that a contact binary system would merge into a rapidly rotating single star due to tidal instability when the spin angular momentum of the system is more than a third of its orbital angular momentum. Assuming…
W UMi is a near contact, semi-detached, double-lined eclipsing binary star with an orbital period of 1.7 days. Simultaneous analysis of new BVR multi-color light curves and radial velocity data yields the main astrophysical parameters of…
The study of very short-period contact binaries provides an important laboratory in which the most important and problematic astrophysical processes of stellar evolution take place. Short-period contact systems, such as CC Com are…
The observations of W UMa type stars show a well-defined short-period limit of 0.22 d, which is equivalent to a lower mass limit of approximately 1 solar mass for the total binary mass. It is currently believed that cool contact binaries…
Results are presented on component masses and system angular momenta for over a hundred low-temperature contact binaries. It is found that the secondary components in close binary systems are very similar in mass. Our observational evidence…