Related papers: Cyclical period changes in cataclysmic variables: …
We present the results for orbital period analysis of 9 contact binaries (CBs). The photometric data analyzed in this work is collected using ARIES 1-m and 1.3-m telescopes as well as many ground and space-based photometric surveys. The…
The population of non magnetic cataclysmic variables evolving under the influence of a circumbinary disk is investigated for systems above the upper edge of the period gap at orbital periods greater than 2.75hr. For a fractional mass input…
Cataclysmic Variables (CVs) are interacting binaries consisting of at least three components that control their colour and magnitude. Using Gaia we here investigate the influence of the physical properties of these binaries on their…
So far, stellar population studies have mainly focused on the evolution of single and binary stars. Recent observations show that triple and higher order multiple star systems are common, especially among massive stars. Introducing…
Analyzing the available photometry from the Kepler satellite and other databases, we performed detailed light curve modeling of 10 eclipsing binary systems that were found to exhibit a periodic modulation of their orbital periods. All of…
A nonlinear nature of the binary ephemeris of Cygnus X-3 indicates either a change in the orbital period or an apsidal motion of the orbit. We have made extended observations of Cygnus X-3 with the Pointed Proportional Counters (PPCs) of…
We report the identification of cyclical changes in the orbital period of the eclipsing dwarf novae V2051 Ophiuchi and V4140 Sagitarii. We used sets of white dwarf mid-eclipse timings to construct observed-minus-calculated diagrams…
We model cataclysmic variables (CVs) with solar metallicity donors ($X=0.7,\:Z=0.02$) that evolve to form AM CVn stars through the Evolved CV formation channel using various angular momentum loss mechanisms by magnetic braking…
We produce and analyze eclipse time variation (ETV) curves for some 2600 Kepler binaries. We find good to excellent evidence for a third body in 222 systems via either the light-travel-time (LTTE) or dynamical effect delays. Approximately…
Four eclipsing binaries, which show apparent changes of period, have been studied with respect to a possible presence of the light time effect. With a least squares method we calculated new light elements of these systems, the mass function…
By using available archival X-ray data, we significantly extended the list of times of X-ray minima. The new list includes 65 data points obtained by critically re-analyzing RXTE ASM data, 88 data points based on observations by MAXI, and…
The chemical enrichments detected in CEMP-$s$ stars are believed to be the consequence of a mass-transfer episode from a now extinct AGB primary star. This hypothesis is borne out by the fact that most CEMP-$s$ stars exhibit RV variations…
We present a comprehensive study of Z CVn, an RR Lyrae star that shows long-term cyclic variations of its pulsation period. A possible explanation suggested from the shape of the O-C diagram is the light travel-time effect, which we…
SuperWASP light curves for 53 W UMa-type eclipsing binary (EB) candidates, identified in previous work as being close to the contact binary short-period limit, were studied for evidence of period change. The orbital periods of most of the…
We present here results of numerical calculations demonstrating that the very long periodic variability detected in the Cataclysmic Variable FS Aur can be the result of eccentricity modulation of a close binary (CB) orbit induced by the…
More than 20 pre-cataclysmic variable (pre-CV) systems have now been discovered with very short orbital periods ranging from 250 min down to 68 min. A pre-CV consists of a white dwarf or hot subdwarf primary and a low-mass companion star,…
The period changes of contact binaries obtained by the analysis of eclipse minima timing are found mostly chaotic in nature. However, they are representable by a few cyclic changes superposed on a secular change. The cyclic changes are…
Strong selection effects are present in observational samples of cataclysmic variables (CVs), complicating comparisons to theoretical predictions. The selection criteria used to define most CV samples discriminate heavily against the…
CSS1603+19 is a cataclysmic variable (CV) with an orbital period of 81.96 min, near the minimal period of cataclysmic variables. It is unusual in having a strong mid-infrared excess inconsistent with thermal emission from a brown dwarf…
We present spectroscopy and orbital periods Porb for 30 apparently non-magnetic cataclysmic binaries with periods below about 3 hours, nearly all of which are dwarf novae, mostly of the SU Ursae Majoris subclass. We then turn to the…