Related papers: HD 63021: Chromospheric Activity and Mass Transfer…
We report the results of a long-term spectroscopic monitoring of the FS\,CMa type object MWC\,728. We found that it is a binary system with a B5 Ve (T$_{\rm eff}$ = 14000$\pm$1000 K) primary and a G8 III type (T$_{\rm eff} \sim$ 5000 K)…
The measurement of the apsidal motion in close eccentric massive binary systems provides essential information to probe the internal structure of the stars that compose the system. Following the determination of the fundamental stellar and…
We present the first comprehensive photometric and spectroscopic analysis of the RS CVn system HD 26172, robustly determining the previously debated evolutionary state of its primary star. Since this system is a single-lined spectroscopic…
A new determination of the orbit of the Hyades double-lined spectroscopic binary HD 27149 is presented. The well-defined orbit provides the spectroscopic basis for an extremely accurate orbital parallax for the system -- in particular, the…
We present results from a radial velocity study of two runaway O-type stars, HD 14633 (ON8.5 V) and HD 15137 (O9.5 III(n)). We find that HD 14633 is a single-lined spectroscopic binary with an orbital period of 15.4083 days. The second…
Extreme eclipsing binaries may harbor peculiar physical properties. In this work, we aim to identify a sample of such systems by selecting binaries with pronounced eclipsing light curves, characterized of large variability ($\Delta…
Interacting binary stars undergo evolution that is significantly different from single stars, thus, a larger sample of such systems with precisely determined stellar parameters is needed to understand the complexities of this process. We…
We give a global analysis of mass transfer variations in low-mass X-ray binaries and cataclysmic variables whose evolution is driven by the nuclear expansion of the secondary star. We show that limit cycles caused by irradiation of the…
The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but…
We report results from a search for Galactic high-mass eclipsing binaries. The photometric monitoring campaign was performed in Sloan $r$ and $i$ with the robotic twin refractor RoBoTT at the Universit\"atssternwarte Bochum in Chile and…
V583 Lyr is an extremely low mass ratio Algol-type binary with an orbital period of 11.2580 days. We determined an effective temperature of T_{eff1} = 9000 \pm 350 K from newly observed spectra, which might be an underestimate due to binary…
We report long baseline interferometric observations with the CHARA Array that resolve six previously known double-lined spectroscopic binary systems in the Hyades cluster, with orbital periods ranging from 3 to 358 days: HD 27483, HD…
We present spectroscopy of the optical counterpart to 1RXS J162848.1-41524, also known as the microquasar candidate MCQC J162847-4152. All the data indicate that this X-ray source is not a microquasar, and that it is a single-lined…
Achernar, the closest and brightest classical Be star, presents rotational flattening, gravity darkening, occasional emission lines due to a gaseous disk, and an extended polar wind. It is also a member of a close binary system with an…
The massive semi-detached binary with a long-term decreasing orbital period may involve a rapid mass-transfer phase in Case A, and thus they are good astrophysical laboratories for investigating the evolution of massive binary stars. In…
We report the discovery of 1RXH J082623.6-505741, a 10.4 hr orbital period compact binary. Modeling extensive optical photometry and spectroscopy reveals a $\sim 0.4 M_{\odot}$ K-type secondary transferring mass through a low-state…
We report the first discovery of a transiting circumbinary planet detected from a single sector of TESS data. During Sector 21, the planet TIC 172900988b transited the primary star and then 5 days later it transited the secondary star. The…
The intriguing binary LS V +22 25 (LB-1) has drawn much attention following claims of it being a single-lined spectroscopic binary with a 79-day orbit comprising a B-type star and a ~70 Msun black hole. Recent analyses have implied that the…
We present extensive spectroscopy and photometry of the dwarf nova V630 Cassiopeiae. A late-type (K4-5) absorption spectrum is easily detectable, from which we derive the orbital parameters. We find a spectroscopic period of P=2.56387 +/-…
The new discovered short-period close binary star, XY LMi, was monitored photometrically since 2006. It is shown that the light curves are typical EW-type and show complete eclipses with an eclipse duration of about 80 minutes. By analyzing…