Related papers: Contact Binaries
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…
Possible M-type contact binaries were investigated by selecting W UMa-type variables with orbital periods below the 0.22-day cutoff. Gaia parallaxes were combined with Gaia and 2MASS photometry to obtain G and J-band absolute magnitudes of…
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…
Context. It is common for massive stars to engage in binary interaction. In close binaries, the components can enter a contact phase, where both stars overflow their respective Roche lobes simultaneously. While there exist observational…
The minimum mass ratio for tidal stability of a contact binary containing two unevolved main-sequence stars is calculated to be $\qmin\simeq0.09$ in the case of a mostly radiative primary, and is higher if an appreciable fraction of the…
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…
This paper presents the results of a combined spectroscopic and photometric study of 20 contact binary systems: HV Aqr, OO Aql, FI Boo, TX Cnc, OT Cnc, EE Cet, RWCom, KR Com, V401 Cyg, V345 Gem, AK Her, V502 Oph, V566 Oph, V2612 Oph, V1363…
The luminosity function for contact binary stars of the W~UMa-type is evaluated on the basis of the ASAS photometric project covering all stars south of delta= +28 within a magnitude range 8<V<13. Lack of colour indices enforced a…
Symbiotic stars are long-period interacting binary systems in which an evolved red giant star transfers material to its much hotter compact companion. Such a composition places them among the most variable stars. In addition to periodic…
ZZ UMa is a detached eclipsing binary with an orbital period of 2.299 d that shows total eclipses and starspot activity. We used five sectors of light curves from the Transiting Exoplanet Survey Satellite (TESS) and two published sets of…
The structure and evolution of low mass W UMa type contact binaries are discussed by employing Eggleton's stellar evolution code. Assuming that these systems completely satisfy Roche geometry, we calculate the relative radii of both…
We have attempted to establish an observational evidence for presence of distant companions which may have acquired and/or absorbed the angular momentum during evolution of multiple systems thus facilitating or enabling formation of contact…
We present the first UBV and uvby photometric observations for the short period variable star HV Ursae Majoris classified as a field RRc variable. The observed differences between the consecutive minima and the lack of colour variations…
II UMa is a late F-type (F5) contact binary with a close-in tertiary and a distant visual companion. According to the four-color ($B$ $V$ $R_c$ $I_c$) light curves' solutions of II UMa, it is a high fill-out (f=$86.6\,\%$) and low mass…
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…
In radiative layers of rotating stars the luminosity carried by circulation currents through a surface of constant entropy (circulation luminosity) is shown to be positive. The corresponding decrease in the temperature gradient is important…
Stars are mostly found in binary and multiple systems, as at least 50% of all solar-like stars have companions - a fraction that goes up to 100% for the most massive stars. Moreover, a large fraction of them will interact in some way or…
A hydrodynamic model for the energy transport between the components of a contact binary is presented. Energy is transported by a large-scale, steady circulation carrying high entropy matter from the primary to secondary component. The…
Binary interactions are commonplace among massive stars, giving rise observed phenomena such as X-ray binaries, stripped stars & supernovae, and gravitational-wave sources. The multiplicity properties of massive stars thus represent a…
Stellar models of massive single stars are still plagued by major uncertainties. Testing and calibrating against observations is essential for their reliability. For this purpose one preferably uses observed stars that have never…