We analyse the CoRoT and V-passband ground-based light curves of the interacting close binary AU Mon, assuming that there is a geometrically and optically thick accretion disc around the hotter and more massive star, as inferred from the photometric and spectroscopic characteristics of the binary. Our model fits the observations very well and provides estimates for the orbital elements and physical parameters of the components and of the accretion disc.

We present a spectroscopic and photometric study of the Double Period Variable HD 170582. Based on the study of the ASAS V-band light curve we determine an improved orbital period of 16.87177 ± 0.02084 days and a long period of 587 days. We disentangled the light curve into an orbital part, determining ephemerides and revealing orbital ellipsoidal variability with unequal maxima, and a long cycle, showing quasi-sinusoidal changes with amplitude ∆V= 0.1 mag. Assuming synchronous rotation for the cool stellar component and semi-detached configuration we find a cool evolved star of M 2 = 1.9 ± 0.1 M , T 2 = 8000 ± 100 K and R 2 = 15.6 ± 0.2 R , and an early B-type dwarf of M 1 = 9.0 ± 0.2 M . The B-type star is surrounded by a geometrically and optically thick accretion disc of radial extension 20.8 ± 0.3 R contributing about 35% to the system luminosity at the V band. Two extended regions located at opposite sides of the disc rim, and hotter than the disc by 67% and 46%, fit the light curve asymmetries. The system is seen under inclination 67.4 ± 0.4 degree and it is found at a distance of 238 ± 10 pc. Specially interesting is the double line nature of He i 5875; two absorption components move in anti-phase during the orbital cycle; they can be associated with the shock regions revealed by the photometry. The radial velocity of one of the He i 5875 components closely follows the donor radial velocity, suggesting that the line is formed in a wind emerging near the stream-disc interacting region.

We observed the post-common-envelope eclipsing binary with a white dwarf component, QS Vir, using the 1.88 m telescope of Kotammia Observatory in Egypt. The new observations were analyzed together with all multicolor light curves available online (sampling a period of 25 years), using a full-feature binary system modeling software based on Roche geometry. This is the first time complete photometric modeling was done with most of these data. QS Vir is a detached system, with the red dwarf component underfilling its Roche lobe by a small margin. All light curves feature out-of-eclipse variability that is associated with ellipsoidal variation, mutual irradiation and irregularities in surface brightness of the tidally distorted and magnetically active red dwarf. We tested models with one, two and three dark spots and found that one spot is sufficient to account for the light curve asymmetry in all datasets, although this does not rule out the presence of multiple spots. We also found that a single spotted model cannot fit light curves observed simultaneously in different filters. Instead, each filter requires a different spot configuration. To thoroughly explore the parameter space of spot locations, we devised a grid-search procedure and used it to find consistent solutions. Based on this, we conclude that the dark spot responsible for light curve distortions has been stable for the past 15 years, after a major migration that happened between 1993 and 2002, possibly due to a flip-flop event.

We present a detailed study of the active eclipsing binary V455 Cygni (V455 Cyg), based on spectroscopic and photometric data from the 1.25-m and 0.6-m telescopes at the Crimean SAI Observatory and the 0.6-m telescope at the Maidanak Observatory, collected in the period from 2000 to 2010.Spectroscopic evidence and the shape of the light curves suggest the existence of a geometrically and optically thick accretion disc around the more massive and hotter gainer. We used a model of the binary system based on the Roche geometry and including the accretion disc with active regions to estimate the orbital and physical parameters of the components of V455 Cyg. Our model fits the observations very well for all individual passband light curves.The evident seasonal changes in the shape of the light curves, including prominent variations in the depth of the eclipses, can be explained by the changes in the parameters of the accretion disc and the active regions of the disc, arising in turn from a variable rate of mass transfer.

The paper presents an analysis of photometric observations of the eclipsing binary QW Gem. The orbital and physical parameters of the system are derived using the modeling code by G. Djurašević. Photometric observations are obtained from the SuperWASP public archive and the spectroscopic elements are adopted from a recently published radial velocity study. The results suggest that QW Gem is a binary in overcontact configuration, consisting of two stars of similar surface brightness but in different evolutionary stages