Related papers: ROTSE1 J164341.65+251748.1: a new W UMa-type eclip…
The first multicolor observations and light curve solutions of the stars 1SWASP J130111.22+420214.0 and 1SWASP J231839.72+352848.2 are presented. The estimated physical parameters of 1SWASP J130111.22+420214.0 are $M_1=1.0M_{\odot}$,…
We calculated physical and orbital properties for 2M06464003+0109157, a 1.06 day eclipsing double lined spectroscopic binary. We modelled the system's ASAS-SN and TESS light curves, measuring the system's inclination and radii of each…
We have found a new low-mass, double-lined, detached eclipsing binary, GU Boo, among a sample of new variables from the ROTSE-I database. The binary has an orbital period of 0.488728 +/- 0.000002 days, and estimated apparent magnitudes…
We present spectroscopy and time-series photometry of the newly discovered dwarf nova 1RXS J232953.9+062814. Photometry in superoutburst reveals a superhump with a period of 66.06(6) minutes. The low state spectrum shows Balmer and HeI…
We present the discovery and characterisation of the post-common-envelope central star system in the planetary nebula PN G283.7$-$05.1. Deep images taken as part of the POPIPlaN survey indicate that the nebula may possess a bipolar…
We report spectroscopic observations of the 2.63 day, detached, F-type main-sequence eclipsing binary V2154 Cyg. We use our observations together with existing $uvby$ photometric measurements to derive accurate absolute masses and radii for…
Reliable determination of the basic physical properties of hot emission-line binaries with Roche-lobe filling secondaries is important for developing the theory of mass exchange in binaries. It is a very hard task, however, which is…
The archival spectrum of SDSS J212531.92-010745.9 shows not only the typical signature of a PG1159 star, but also indicates the presence of a companion. With time-series photometry of SDSS J212531.92-010745.9 during 10 nights, spread over…
We present an analysis of LAMOST J171013.211+532646.04 (hereafter J1710), a binary system comprising a hot subdwarf B star (sdB) and a white dwarf (WD) companion. Multi-epoch spectroscopy reveals an orbital period of 109.20279 minutes,…
The first V Rc Ic bands light curves of MQ UMa are presented and analyzed using the Wilson-Devinney (W-D) program. It is discovered that MQ UMa is an A-subtype contact binary with a high fill-out (f=82 %) and a low mass ratio (q = 0:195),…
We present the orbital solution for the donor star of the candidate transitional millisecond pulsar 3FGL J1544.6-1125, currently observed as an accreting low-mass X-ray binary. The orbital period is $0.2415361(36)$ days, entirely consistent…
We analyze multicolor light curves of six totally eclipsing, short-period W UMa binaries and derive, for the first time, their orbital and stellar parameters. The mass ratios are established robustly through an automated q-search procedure…
We have investigated multiband optical photometric variability and stability of the H$\alpha$ line profile of the transient X-ray binary IGR J01583+6713. We set an upper limit of 0.05 mag on photometric variations in the {\it V} band over a…
New BVRI light curves of the eclipsing binary system 1SWASP J160156.04+202821.6 have been obtained with the 1.88-m telescope of Kottamia Astronomical Observatory (KAO), Egypt on June, 2013. New twenty times of minima of the system J1601 and…
We present new V-band differential brightness measurements as well as new radial-velocity measurements of the detached, circular, 0.84-day period, double-lined eclipsing binary system CV Boo. These data along with other observations from…
Dedicated monitoring of the transient X-ray pulsar XTE J1543-568 during the first year after its discovery has revealed the unambiguous detection of a binary orbit. The orbital period is 75.56+/-0.25 d, and the projected semi-major axis…
The bright southern binary star beta Centauri (HR 5267) has been observed with the Sydney University Stellar Interferometer (SUSI) and spectroscopically with the ESO CAT and Swiss Euler telescopes at La Silla. The interferometric…
We present optical spectroscopy and extensive $RI$ differential photometry of the double-lined eclipsing binary NSVS 02502726 (2MASS J08441103+5423473). Simultaneous solution of two-band light curves and radial velocities permits…
From the radial velocities of the N IV 4058 and He II 4686 emission lines, and the N V 4604-20 absorption lines, determined in digital spectra, we report the discovery that the X-ray bright emission line star Wack 2134 (= WR 21a) is a…
The star ASAS J174600-2321.3 was found to exhibit peculiar photometric variability (conspicuous brightening of about 4 magnitudes (V), fast luminosity declines, intrinsic pulsations). It was rejected as an RCB candidate in recent…