Related papers: Line-profile variability from tidal flows in Alpha…
Particle Image Velocimetry (PIV) has become increasingly popular to study structures in turbulent flows. PIV allows direct extraction and investigation of spatial structures in the given flow field. Increasing temporal resolution of PIV…
The three objects have been identified as members of the recently recognized class of Gamma Doradus stars, which exhibit multi-periodic photometric variations that are thought to arise from non-radial pulsation. The particular objects…
H{\alpha} emission V/R variations caused by a discontinous mass transfer in interacting binaries with a rapidly rotating accreting star are modelled qualititatively for the first time. The program ZEUS-MP was used for a non-linear 3-D…
We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All…
In this study, we present a spectroscopic analysis of the bright Be star kappa Dra. Two independent sets of radial velocity velocities (RV) measurements were obtained by direct measurement and using a line profile disentangling technique.…
A number of binary systems present evidence of enhanced activity around periastron passage, suggesting a connection between tidal interactions and these periastron effects. The aim of this investigation is to study the time-dependent…
We present preliminary results of our spectroscopic campaign of a group of intermediate mass interacting binaries dubbed "Double Periodic Variables" (DPVs), characterized by orbital light curves and additional long photometric cycles…
(Abbreviated) We extend the results of our 2021 paper concerning the problem of tidal evolution of a binary system with a rotating primary component with rotation axis arbitrarily inclined with respect to the orbital plane. Only the…
The Wolf-Rayet star WR 46 is known to exhibit a very complex variability pattern on relatively short time scales of a few hours. Periodic but intermittent radial velocity shifts of optical lines as well as multiple photometric periods have…
Solar limb and disc spicule quasi- periodic motions have been reported for a long time, strongly suggesting that they are oscillating. In order to clear up the origin and possibly explain some solar limb and disc spicule quasi-periodic…
The X-ray source 2S0114+650=LSI+65 010 is a binary system containing a B-type primary and a low mass companion believed to be a neutron star. The system has three reported periodicities: the orbital period, P{orb}~11.6 d, X-ray flaring with…
We investigate line formation in gas that is outflowing and optically thick to electron scattering, as may be expected following the tidal disruption of a star by a super-massive black hole. Using radiative transfer calculations, we show…
Optical turbulence occurring in the oceanic waters may be detrimental for light beams used in the short-link communication and sensing systems, and, in particular, in underwater LIDARs. We develop a theory capable of predicting the passage…
We have investigated line profiles in a large sample of Cepheid spectra, and found four stars that show unusual (for Cepheids) line profile structure (bumps or/and asymmetries). The profiles can be phase dependent but the behavior persists…
A new semi-analytical model of a star evolving in a tidal field is proposed. The model is a generalization of the so-called 'affine' stellar model. In our model the star is composed of elliptical shells with different parameters and…
Tidal friction has long been recognized to circularize the orbits of binary stars over time. In this study, we use the observed distribution of orbital eccentricities in populations of binary stars to probe tidal dissipation. In contrast to…
This paper uses statistical and $N$-body methods to explore a new mechanism to form binary stars with extremely large separations ($> 0.1\,{\rm pc}$), whose origin is poorly understood. Here, ultra-wide binaries arise via chance entrapment…
We describe the construction of a highly reliable sample of approximately 7,000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 sq.deg of northern sky. Majority of these…
Spectral-line displacements away from the wavelengths naively expected from the Doppler shift caused by stellar radial motion may originate as convective shifts (correlated velocity and brightness patterns in the photosphere), as…
We present a spectrophotometric study of short-term optical variability in the quiescent black hole X-ray transient V404 Cyg. This includes two nights of high time-resolution Halpha spectroscopy with which we resolve much of the…