Related papers: HV Ursae Majoris, a new contact binary with early-…

Photometric observations in V and I bands and low-dispersion spectra of ten ultrashort-period binaries (NSVS 2175434, NSVS 2607629, NSVS 5038135, NSVS 8040227, NSVS 9747584, NSVS 4876238, ASAS 071829-0336.7, SWASP 074658.62+224448.5, NSVS…

Multiband photometric investigations for eight binary systems of the W Ursae Majoris (W UMa)-type are presented. Six systems are presented for the first time to analyze their light curves. All the analyzed systems have a temperature below…

We report the discovery of a bright (V=11.6 mag) eclipsing hot subdwarf binary of spectral type B with a late main sequence companion from the All Sky Automated Survey (ASAS 102322-3737.0). Such systems are called HW Vir stars after the…

EZ Canis Majoris is a classical Wolf-Rayet star whose binary nature has been debated for decades. It was recently modeled as an eccentric binary with a periodic brightening at periastron of the emission originating in a shock heated zone…

High resolution spectroscopic observations of AW UMa, obtained on three consecutive nights with the median time resolution of 2.1 minutes, have been analyzed using the Broadening Functions method in the spectral window Doppler images of the…

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…

We confirmed the binary nature of the Be star 7~Vul, derived a~more accurate spectroscopic orbit with an orbital period of (69.4212+/-0.0034) d, and improved the knowledge of the basic physical elements of the system. Analyzing available…

Because of the similarity of the primary star of HS 1136+6646 to the planetary nebula central star BE Ursae Majoris, we did wide field imaging of the former with an H-alpha filter. No nebulosity was detected. On the other hand, the point…

Using multicolour photometry we have confirmed the binary nature of the new W-type W UMa eclipsing binary VSX J053024.8+842243 and established its primary eclipse ephemeris to be HJD = 2455924.38150(26) + 0.4322929(1) * E. Using the light…

Multi-color light curves of V1197 Her were obtained with the 2.4 meter optical telescope at Thai National Observatory and the Wilson-Devinney (W-D) program is used to model the observational light curves. The photometric solutions reveal…

Time-resolved CCD photometry is presented of the recently-discovered (V~15 at maximum light) eruptive variable star in Taurus, which we dub VS0329+1250. A total of ~20 hr of data obtained over six nights reveals superhumps in the light…

Hot subdwarf stars represent a late and peculiar stage in the evolution of low-mass stars, because they are likely formed by close binary interactions. Here we performed a radial velocity (RV) variability study of a sample of 646 hot…

Luminous Blue Variables (LBVs) are massive stars caught in a post-main sequence phase, during which they are losing a significant amount of mass. As, on one hand, it is thought that the majority of massive stars are close binaries that will…

Optical high-resolution spectra of the R Coronae Borealis star V CrA at light maximum and during minimum light arediscussed. Abundance analysis confirms previous results showing that V CrA has the composition of the small subclass of R…

We present a system model for optical and far UV spectra of the nova-like variable UX UMa involving a white dwarf, secondary star, gas stream, hot spot and accretion disk using our code BINSYN and based on an initially adopted system…

We present far-ultraviolet (905 -- 1182 A), time-series spectroscopy of the eclipsing, novalike cataclysmic variable, UX UMa, acquired with FUSE. The time-averaged spectrum is complex and is dominated by overlapping spectral features. The…

Aims: Detect tertiary components of close binaries from spectroscopy and light curve modelling; investigate light-travel time effect and the possibility of magnetic activity cycles; measure mass-ratios for unstudied systems and derive…

We present the multi-band photometric and low-resolution spectroscopic analysis of four W Ursae Majoris eclipsing binaries (EWs) - J080510.1+141528 (hereinafter as J0805a), J080516.3+143138 (hereinafter as J0805b), J143358.7+053953…

In this Letter, the radial velocity variability of the chemically peculiar star Epsilon Ursae Majoris ($\epsilon$ UMa) from the sharp cores of the hydrogen lines is investigated. This study is based on the ELODIE archival data obtained at…

A sample of bright contact binary stars (W UMa-type or EW, and related: with beta Lyr light curves, EB, and ellipsoidal, ELL - in effect, all but the detached, EA), to the limit of Vmax = 7.5 magnitude is deemed to include all discoverable…