Related papers: Multiwavelength optical observations of two chromo…
Within the scope of extended matter research, we present new spectral analysis results of an active binary system AR Lac. The low and high resolution spectra of this system were taken during the period 2013-2016. The evaluation of low…
Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the second set of ten contact binary systems. Eight systems are of the A-type: AH Aur, CK Boo, DK Cyg, UZ Leo, XZ Leo, V839 Oph, GR…
The star EZ Peg, long ago classified as cataclysmic variable, has been shown to be a chromospherically active binary system of the RS CVn-type. In this paper we have analysed, using the spectral subtraction technique, simultaneous…
Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been derived for 13 chemical species, including…
Effective temperatures, surface gravities, and iron abundances were derived for 109 stars observed by the K2 mission using equivalent width measurements of Fe I and Fe II lines. Calculations were carried out in LTE using Kurucz model…
In this work we analyze the behaviour of the excess Ca~{\sc ii} H \& K and H$\epsilon$ emissions in a sample of 73 chromospherically active binary systems (RS$~$CVn and BY$~$Dra classes), of different activity levels and luminosity classes.…
The high-resolution optical spectra of the two X-ray active binaries RS CVn stars HD 113816 (IS Vir) and HD 119285 (V851 Cen) are analysed and their Na, Mg, Al, Si, Ca, Sc, Ti, Co and Ni contents determined. The analysis of IS Vir and V851…
We present the first in a series of papers that attempt to investigate the relation between binarity, magnetic activity, and chemical surface abundances of cool stars. In the current paper, we lay out and test two abundance analysis methods…
We present preliminary results of follow-up optical observations, both photometric and spectroscopic, of stellar X-ray sources, selected from the cross-correlation of ROSAT All-Sky Survey (RASS) and TYCHO catalogues. Spectra were acquired…
OO Aql is a rare W UMa-type eclipsing binary in which the two solar-type stars may have only recently evolved into contact. The binary has an unusually high mass ratio (0.84), and a relatively long orbital period (0.506 d) for it spectral…
Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the eighth set of ten close binary systems: AB And, V402 Aur, V445 Cep, V2082 Cyg, BX Dra, V918 Her, V502 Oph, V1363 Ori, KP Peg, V335…
Aims: We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood which may be used to investigate different aspects of the formation and evolution of the solar…
High resolution echelle spectra of PW And (HD~1405) have been taken during eight observing runs from 1999 to 2002. The detailed analysis of the spectra allow us to determine its spectral type (K2V), mean heliocentric radial velocity (V_hel…
We present the results of time-resolved spectroscopy of 13 O-type stars in the Cas OB6 stellar association. We conducted a survey for radial velocity variability in search of binary systems, which are expected to be plentiful in young OB…
Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution \'echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon.…
The hierarchical multiple system XY Leo, despite nearly 90 yr of observations, remains enigmatic. It offers a unique testbed for close binary evolution, involving processes such as mass transfer, angular momentum loss, and the von…
We present new spectroscopic observations in the Ca~{\sc ii} H \& K line region for a sample of 28 chromospherically active binary systems (RS$~$CVn and BY$~$Dra classes), with different activity levels. By using the spectral subtraction…
We present an analysis of long-term optical monitoring observations and optical spectroscopic observations of the counterpart to CXOU J205847.5+414637 (high mass X-ray binary system). We search for a variability in the light curve of Be…
We present the results of our 2nd radial velocity monitoring campaign, carried out with the \'Echelle spectrograph FLECHAS at the University Observatory Jena in the course of the Gro{\ss}schwabhausen binary survey between December 2016 and…
Several late-type stars present activity cycles similar to that of the Sun. However, these cycles have been mostly studied in F to K stars. Due to their small intrinsic brightness, M dwarfs are not usually the targets of long-term…