Related papers: Newly discovered active binaries in the RasTyc sam…
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 cross-correlation between the ROSAT all-sky survey (~150000 sources) and the Tycho mission (~1000000 stars) catalogs has selected about 14000 stellar X-ray sources (RasTyc sample, Guillout et al. 1999). About 200-300 stars have been…
Context. This work is part of a long-term spectroscopic study of a sample of 30 multiple stars with early-type components. In this second paper we present the results of six multiple systems in which new stellar components have been…
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…
During the study of a large set of late-type stellar X-ray sources, we discovered a large fraction of multiple systems. In this paper we investigate the orbital elements and kinematic properties of three new spectroscopic triple systems as…
We report the results of our radial-velocity monitoring of spectroscopic binary systems in a sample of X-ray sources from the ROSAT All Sky Survey south of the Taurus-Auriga star-forming region. The original sample of approximately 120…
Star formation in the solar neighborhood is mainly traced by young stars in open clusters, associations and in the field, which can be identified by their X-ray emission. The determination of stellar parameters for the counterparts of X-ray…
We present results of the analysis of light and radial velocity (RV) curves of eight detached eclipsing binaries observed by the All-Sky Automated Survey, which we have followed up with high-resolution spectroscopy, and were later observed…
CONTEXT. Many O-type stars have nearby companions whose presence hamper their characterization through spectroscopy. AIMS. We want to obtain spatially resolved spectroscopy of close O-type visual binaries to derive their spectral types.…
We present an analysis of nine bright spectroscopic binaries (HD 1585, HD 6613, HD 12390, HD 39923, HD 55201, HD 147430, HD 195543, HD 202699, HD 221643), which have orbital periods of P > 500 days. These well-separated binaries are the…
We present optical lightcurves of 428 periodic variable stars coincident with ROSAT X-ray sources, detected using the first run of the SuperWASP photometric survey. Only 68 of these were previously recognised as periodic variables. A…
Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for the last eight close binary systems analyzed the same way as in the previous papers of this series: QX And, DY Cet, MR Del, HI Dra,…
In a well-aimed search based on the recently published Gaia~DR2 radial velocity data and performed with the robotic TIGRE telescope, we have discovered 19 bright ($m_V<7.66$~mag) spectroscopic binary stars. We present the radial velocity…
We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We…
We present multi-epoch spectroscopy of "heartbeat stars," eccentric binaries with dynamic tidal distortions and tidally induced pulsations originally discovered with the Kepler satellite. Optical spectra of six known heartbeat stars using…
Studying chromospheric activity of contact binaries is an important way of revealing the magnetic activity processes of these systems. An efficient but somewhat neglected method for that is to follow the changes of the H$\alpha$ line…
We report the discovery of a new BY Dra-type binary identified as the optical counterpart of the bright source RX J0222.4+4729 detected during the ROSAT All-Sky Survey (Voges et al. 1996). The star is a $V \sim 11.1$, near-by ($\sim 30$…
The formation of spectroscopic binaries (SB) may be a natural byproduct of star formation. The early dynamical evolution of multiple stellar systems after the initial fragmentation of molecular clouds leaves characteristic imprints on the…
Eclipsing binaries (EBs) play an important astrophysical role in studying stellar properties and evolution. By analyzing photometric data in the LAMOST Medium-Resolution Survey field, RA: $23^h$$01^m$$51.00^s$, Dec:…
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…