Related papers: Absolute properties of the neglected eclipsing B-t…

In a well-aimed search based on the recently published Gaia~DR2 radial velocity data and performed with the robotic TIGRE telescope, we have discovered 19 bright ($m_V<7.66$~mag) spectroscopic binary stars. We present the radial velocity…

We report spectroscopic observations of the star HIP 50796, previously considered (but later rejected) as a candidate member of the TW Hya association. Our measurements reveal it to be a single-lined binary with an orbital period of 570…

The predicted orbital-period distribution of the subdwarf-B (sdB) population is bi-modal with a peak at short (< 10 days) and long (> 250 days) periods. Observationally, many short-period sdB systems are known, but the predicted long period…

The young nearby solar-type star HD 91962 is a rare quadruple system where three companions revolve around the main component with periods of 170.3 days, 8.85 years, and 205 years. The two outer orbits are nearly co-planar, and all orbits…

We used very long baseline interferometry to constrain the orbit of the binary system 2MASS J05082729-2101444. We observed the system with the VLBA in three epochs at a frequency of 4.85 GHz, which provides an angular resolution of about 3…

KIC 7177553 is a quadruple system containing two binaries of orbital periods 16.5 and 18 d. All components have comparable masses and are slowly rotating, non-evolved stars of spectral type near G2V. The longer period binary is eclipsing…

Several nearby solar-type dwarfs with variable radial velocity were monitored to find their spectroscopic orbits. First orbital elements of 15 binaries (HIP 12144, 17895, 27970, 32329, 38636, 39072, 40479, 43004, 73700, 79234, 84696, 92140,…

We present a complex study of the eclipsing binary system, AB Cas. The analysis of the whole TESS light curve, corrected for the binary effects, reveals 112 significant frequency peaks with 17 independent signals. The dominant frequency…

NGC 7789 is an intermediate-age open cluster with an age that is similar to the mean age of contact binary stars. V12 is a bright UMa-type binary star with an orbital period of 0.397 day. The first complete light curves of V12 in V, R, and…

As part of an ongoing programme of observing detached eclipsing binary stars in the southern sky, we present the first analysis of spectroscopic observations of the Algol-type binary system DG Mic. A spectroscopic analysis of mid-resolution…

We have determined spectroscopic orbits for five single-lined spectroscopic binaries, HD 100167, HD 135991, HD 140667, HD 158222, HD 217924. Their periods range from 60.6 to 2403 days and the eccentricities, from 0.20 to 0.84. Our spectral…

We describe a newly-discovered detached M-dwarf eclipsing binary system, the fourth such system known. This system was first observed by the TrES network during a long term photometry campaign of 54 nights. Analysis of the folded light…

We present time-resolved optical spectroscopy of the dwarf nova CSS100603:112253-111037. Its optical spectrum is rich in helium, with broad, double-peaked emission lines produced in an accretion disc. We measure a line flux ratio…

We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We…

We present the results of our study of the long-period eclipsing binary star \Aur. The results are based on spectroscopic data obtained with the UFES \'echelle spectrograph and photometric observations from TESS. The derived radial velocity…

We found that the known spectroscopic binary and variable BU~CMi = HD65241 ($V$=6.4-6.7 mag, Sp~=~A0~V) is a quadruple doubly eclipsing 2+2 system. Both eclipsing binaries are detached systems moving in an eccentric orbits: pair "A" with…

V1765 Cyg is a detached eclipsing binary containing a B0.5 supergiant and a B1 main-sequence star, with an orbital period of 13.37 d and an eccentricity of 0.315. The system shows apsidal motion and the supergiant exhibits strong stochastic…

K2 observations of the weak-lined T Tauri binary V928 Tau A+B show the detection of a single, asymmetric eclipse which may be due to a previously unknown substellar companion eclipsing one component of the binary with an orbital period $>$…

We present the results of 37 nights of CCD unfiltered photometry of nova V2574 Oph (2004) from 2004 and 2005. We find two periods of 0.14164 d (~3.40 h) and 0.14773 d (~3.55 h) in the 2005 data. The 2004 data show variability on a similar…

We present UBVRI photometric measurements and spectroscopic observations of the double-lined eclipsing binary V821 Cas. The radial velocities were obtained by means of the cross-correlation technique. Simultaneous analyses of the multi-band…