Related papers: The contact binary V344 Lacertae: is it a triple s…
We present the high precession photometric studies in V band and spectroscopic studies centered around H-alpha line for two extreme mass-ratio short period contact binaries ASAS J082243+1927.0 (V1) and ASAS J085710+1856.8 (V2). The…
New spectroscopic observations of the LBV/WR multiple system HD5980 in the Small Magellanic Cloud are used to address the question of the masses and evolutionary status of the two very luminous stars in the 19.3d eclipsing binary system.…
Extreme mass-ratio contact binaries with a high degree of overcontact may be in the late evolutionary stages of the contact phase. Detailed photometric analyses and orbital period studies of those systems can provide invaluable information…
Because many classical Be stars may owe their nature to mass and angular-momentum transfer in a close binary, the present masses, temperatures, and radii of their components are of high interest for comparison to stellar evolution models.…
Both high precision CCD photometric and H$alpha$ line studies are presented for an overcontact binary ASAS J082243+1927.0. The light curve exhibits a total eclipse at secondary minima along with an O'Connell effect. The light curve was…
Two sets of multiple-color ($B, V, R_c, I_c$) light curves of PZ UMa were observed in dependently with the 2.4 meter telescope at the Thai National Observatory and the 1 meter telescope at Yunnan Observatories. The light curves were…
Through the combination of high-order Adaptive Optics and coronagraphy, we report the discovery of a faint stellar companion to the A3V star zeta Virginis. This companion is ~7 magnitudes fainter than its host star in the H-band, and…
We present the photometric properties of V608 Cas from detailed studies of light curves and eclipse timings. The light curve synthesis indicates that the eclipsing pair is an overcontact binary with parameters of $\Delta T$ = 155 K, $q$ =…
The light curve analyses and orbital period variations for two contact binary stars, LS Del and V997 Cyg, were presented in this work which was conducted in the frame of the Binary Systems of South and North (BSN) Project. Ground-based…
The photometric solutions of NW Aps reveal that it is a low mass ratio ($q = 0.086$) contact binary system. Investigation of orbital period shows that its orbital period is increasing continuously at a rate of…
We report the discovery via radial velocity of a short-period (P = 2.430420 \pm 0.000006 days) companion to the F-type main sequence star TYC 2930-00872-1. A long-term trend in the radial velocities indicates the presence of a tertiary…
The contact eclipsing binary system XX Leonis (P = 0.97 days, sp A8) has been analysed using the PHOEBE programme, based on the Wilson Devinney code. The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7…
ASAS J174406+2446.8 was originally found as a $\delta$ Scuti-type pulsating star with the period P=0.189068 $days$ by ASAS survey. However, the LAMOST stellar parameters reveal that it is far beyond the red edge of pulsational instability…
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…
V1388 Ori is an early-B type detached eclipsing binary whose physical properties have previously been measured from dedicated spectroscopy and a ground-based survey light curve. We reconsider the properties of the system using…
New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVI filters from the Congarinni Observatory in Australia. The new ephemeris is…
We present a complete set of physical parameters for three early-type eclipsing binary systems in the Large Magellanic Cloud (LMC): OGLE LMC-ECL-17660, OGLE LMC-ECL-18794, and HV 2274, together with the orbital solutions. The first and…
The strongest absorption features with the lower-level excitation potentials $\chi_{\rm low}<1$ eV are found to be split in the high-resolution optical spectra of the post-AGB star V354 Lac taken in 2007--2008. Main parameters,…
We report the discovery of a new eclipsing EL CVn-type binary, consisting of a $\delta$ Sct-type pulsator and a thermally bloated low-mass pre-He white dwarf (WD). Spectroscopy and time-series $BV$ photometry of V1224 Cas were carried out.…
Overcontact binary stars are systems of two stars where the component stars are in contact with each other. This implies that they share a common envelope of gas. In this work we seek signatures of nonlinearity and chaos in these stars by…