相关论文: Multiwavelength optical observations of chromosphe…
The dynamo processes in cool active stars generate complex magnetic fields responsible for prominent surface stellar activity and variability at different time scales. For a small number of cool stars magnetic field topologies were…
The UV and optical spectra from the HST FOS and from the FAST spectrograph at the Whipple Observatory at different phases are analysed, leading to new results about the configuration of AG Peg. Consistent modelling by the code SUMA, which…
We have studied the coronal X-ray emission of the recently discovered short-period eclipsing binary HD 9770 with the BeppoSAX satellite. The data from the Low Energy and Medium Energy Concentrator Spectrometers (LECS & MECS) onboard…
We present the light curve variations of the two active binaries with hot subdwarf component. According to the brightness variations outside of the eclipses, the giant components of the systems are chromospherically active stars. The dark…
2RE J0743+224 (BD +23 1799) is a chromospherically active star selected by X-rays and EUV emission detected in the Einstein Slew Survey and ROSAT Wide Field Camara (WFC) all sky survey, and classified as single-lined spectroscopic binary by…
An accident of misidentification has brought to light the interesting system HD 191588, a new RS CVn-type spectroscopic binary. A radial-velocity study of the primary star, the only seen component, carried out at the Observatoire de…
New high-resolution spectra, of the chromospherically active binary system CF Tuc, taken at the Mt. John University Observatory in 2007, were analyzed using two methods: cross-correlation and Fourier--based disentangling. As a result, new…
Using a time series of high-resolution spectra and high-quality multi-colour photometry, we reconstruct surface maps of the primary component of the RS CVn type rapidly rotating eclipsing binary, SV Cam (F9V + K4V). We measure a mass ratio,…
Altough both components of the bright eclipsing binary $\alpha$ Dra having been resolved using long baseline interferometry and the secondary component shown to contribute some 15\% of the total flux, a spectroscopic detection of the…
Data from 11 years of continuous spectroscopic observations of the active RS CVn-type binary star EI Eridani - gained at NSO/McMath-Pierce, KPNO/Coude Feed and during the MUSICOS 98 campaign - were used to obtain 34 Doppler maps in three…
We report on an X-ray flare detected on the active binary system II~Pegasi with the Swift telescope. The trigger had a 10-200 keV luminosity of 2.2$\times10^{32}$ erg s$^{-1}$-- a superflare, by comparison with energies of typical stellar…
This is the fifth paper in a series aimed at studying the chromospheres of active binary systems using several optical spectroscopic indicators to obtain or improve orbital solution and fundamental stellar parameters. We present here the…
We present time-resolved spectroscopy and photometry of the bright cataclysmic variable LS Peg (= S193). The Balmer lines exhibit broad, asymmetric wings Doppler-shifted by about 2000 km/s at the edges, while the HeI lines show…
Understanding stellar activity in M dwarfs is fundamental to improving our knowledge of the physics of stellar atmospheres and for planet search programmes. High levels of stellar activity (also with flare events) can cause additional…
DG CVn is a binary system in which one of the components is an M type dwarf ultra fast rotator, only three of which are known in the solar neighborhood. Observations of DG CVn by the Swift satellite and several ground-based observatories…
There are several strong K I lines found in the spectra of M dwarfs, among them the doublet near 7700 AA and another doublet near 12 500 AA. We study these optical and near-infrared doublets in a sample of 324 M dwarfs, observed with…
We have investigated the spectral behaviour of II Peg binary system in the ultraviolet band by using International Ultraviolet Explorer observations over fifteen years. The ultraviolet observations show indication of flare activity in the…
We present high resolution echelle spectra taken during four observing runs from 1999 to 2001 of the recently X-ray/EUV selected chromospherically active binary BK Psc (2RE J0039+103). Our observations confirm the single-lined spectroscopic…
The H$\alpha$ and H$\beta$ line profiles of the symbiotic star AG Peg observed on 1998 September (phase $\phi$ = 10.24), display the top narrow double Gaussian and bottom broad (FWHM of 200 -- 400 kms$^{-1}$) components. The…
We present high-precision TESS photometry of V421 Peg (TIC 301747091), an early F-type eclipsing binary containing a candidate $\gamma$ Dor component. The observed short-cadence data allow the detection of pulsation signals, along with…