Related papers: Star-spot distributions and chromospheric activity…
As part of our program to study stellar photospheric and chromospheric activity, we have examined several young solar type stars with activity levels intermediate between the Sun and the very active RS CVn binaries. We have analysed…
We observed AR Lac, an eclipsing RS CVn binary star, with the Chandra High Energy Grating Spectrometer for a total of 100 ks divided into six intervals covering both quadratures and eclipses. We repeated observations at each phase. At least…
HD172189 is a spectroscopic eclipsing binary system with a rapidly-rotating pulsating delta Scuti component. It is also a member of the open cluster IC4756. These combined characteristics make it an excellent laboratory for asteroseismic…
Aims: We carried out high-resolution spectroscopy and BV(I)_C photometric monitoring of the two fastest late-type rotators in the nearby Beta Pictoris moving group, HD199143 (F7V) and CD-641208 (K7V). The motivation for this work is to…
This is the third paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. High resolution echelle spectra including all the optical…
We present high-resolution optical spectra of the young brown-dwarf eclipsing binary 2M0535-05, obtained during eclipse of the higher-mass (primary) brown dwarf. Combined with our previous spectrum of the primary alone (Paper I), the new…
In this paper we present a spectroscopic study of six double-lined binaries, five of which were recently discovered in a high-resolution spectroscopic survey of optical counterparts of stellar X-ray sources. Thanks to high-resolution…
The Hyades K2V+WD system 471 Tau is a prototype post-common envelope system and a likely cataclysmic binary progenitor. We present 10 days of nearly continuous optical photometry by the MOST (Microvariability & Oscillations of STars)…
We report on the discovery of J0644+3344, a bright deeply eclipsing cataclysmic variable (CV) binary. Spectral signatures of both binary components and an accretion disk can be seen at optical wavelengths. The optical spectrum shows broad H…
We quantify the effect of starspots for the orbital elements of the spotted RS CVn binary $\lambda$ Andromedae ($\lambda$ And) and present an empirical correction. The aim is to obtain a more precise orbital solution that can be used to…
A careful investigation of a CCD spectrum of the SB1 system kappa Cnc in the spectral region 3800 A - 8000 A resulted in the discovery of the lines of the secondary star. We then analyzed several short-wavelength range Reticon spectra…
We study the short and long-term variability of the spectroscopic binary SZ Pictoris, a southern RS CVn-type system. We used mid-resolution echelle spectra obtained at CASLEO spanning 18 years, and photometric data from the ASAS database…
We have used archival Hubble Space Telescope observations obtained with the Advanced Camera for Surveys to study the H{\alpha} emission properties of main sequence stars in the globular cluster 47 Tucanae. Using a combination of multi-band…
We present the results of our spectroscopic and photometric analysis of two newly discovered low-mass detached eclipsing binaries found in the All-Sky Automated Survey (ASAS) catalogue: ASAS J093814-0104.4 and ASAS J212954-5620.1. Using the…
We use photometric and spectroscopic observations of the detached eclipsing binary V209 omega Cen to derive the masses, radii, and luminosities of the component stars. The system exhibits total eclipses and, based on the measured systemic…
We present our observations of the low-mass eclipsing binary GJ~3236. We have analyzed a phased $R_C$ light-curve and confirmed previously determined fundamental parameters of the components. We detected evolution of the spot(s) and found…
Aims. Emission lines in polars show complex profiles with multiple components that are typically ascribed to the accretion stream, threading region, accretion spot, and the irradiated secondary-star. In low-state polars the fractional…
To measure the properties of both components of the RS CVn binary sigma Geminorum (sigma Gem), we directly detect the faint companion, measure the orbit, obtain model-independent masses and evolutionary histories, detect ellipsoidal…
By cross-matching the eclipsing binary catalog from TESS with that from LAMOST MRS, semi-detached eclipsing binaries with radial velocities coverage spanning more than 0.3 phases were authenticated. The absolute parameters for these systems…
We present a new analysis of the light curve for the secondary star in the eclipsing binary millisecond pulsar system PSR B1957+20. Combining previous data and new data points at minimum from the Hubble Space Telescope, we have 100%…