Related papers: Multiwavelength optical observations of chromosphe…
This is the first paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. Simultaneous H{alpha}, Na I D{1}, D{2}, and He I D{3} spectroscopic…
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 the study on continuous high-resolution spectroscopic observations of two long-period single-lined RS Canum Venaticorum (RS CVn) binary stars IM Pegasi (IM Peg) and $\sigma$ Geminorum ($\sigma$ Gem), obtained with the Hertzsprung…
We present here a continuation of our ongoing project of multiwavelength optical observations aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features that are…
We present simultaneous spectroscopic observations taken during four observing runs (1996 to 1999) of H_alpha, H_beta, H_epsilon, Ca II H & K, and Ca II IRT lines of the chromospherically active binary BF Lyn. Both components have strong…
We have analysed several multiwavelength optical observations (H_alpha, H_beta, H_epsilon, Ca II H & K, Ca II IRT lines) of chromospherically active binary system OU Gem, taken in three observation runs: March 1996, April 1998 (using the…
We present a study of high-resolution spectra of RS Canum Venaticorum (RS CVn), a prototype of active binary systems. Our data were obtained from 1998 to 2017 using different telescopes. We analyze the chromospheric activity indicators Ca…
Continuous photometric observations of the visible component of the single-line, K2IV spectroscopic binary II Peg carried out by the MOST satellite during 31 consecutive days in 2008 have been analyzed. On top of spot-induced brightness…
Stellar coronal mass ejections (CMEs) have recently attracted much attention for their impacts on stellar evolution and surrounding exoplanets. RS CVn-type stars could produce large flares, and therefore may have frequent CMEs. Here we…
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 synchronously rotating G stars in the detached, short-period (0.7 d), partially eclipsing binary, ER Vul, are the most chromospherically active solar-type stars known. We have monitored activity in the Ca II H & K reversals for almost…
This paper describes a multiwavelengh optical study of chromospheres in two X-ray/EUV selected active binary stars with strong H_alpha emission, V789 Mon (2RE J0725-002) and GZ Leo (2RE J1101+223). The goal of the study is to determine…
We analyze optical and ultraviolet observations of the symbiotic binary AG Pegasi acquired during 1992-97. The bolometric luminosity of the hot component declined by a factor of 2-3 from 1980-1985 to 1997. Since 1992, the effective…
We present a multiwavelength study of three chromospherically active stars, namely FR Cnc (= BD +16\degr 1753), HD 95559 and LO Peg (=BD +22\degr 4409), including newly obtained optical photometry, low-resolution optical spectroscopy for FR…
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…
Magnetic fields of cool active stars are currently studied polarimetrically using only circular polarization observations. Including linear polarization in the reconstruction of stellar magnetic fields allows more information about the…
We present simultaneous and continuous observations of H_alpha, H_beta, NaI D_1, D_2 and HeI D_3 lines of the chromospherically active binary HR 1099. We have observed HR 1099 for more than 3 weeks almost continuously and monitored two…
We have carried out high-speed photometry of three chromospherically active stars, BD +15 3364, II Peg, and SAO 52355 with the Zeiss 2-m telescope, as well as low-resolution spectroscopy of SAO 52355 with the Zeiss-600 telescopes at Peak…
Stellar coronal mass ejections remain experimentally unconstrained, unlike their stellar flare counterparts which are observed ubiquitously across the electromagnetic spectrum. Low frequency radio bursts in the form of a type II burst offer…
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…