New Times of Minima of Eclipsing Binary Systems
We present 82 photoelectric minima observations of 34 eclipsingbinaries.
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A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
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Apsidal motion in southern eccentric eclipsing binaries: V539 Ara, GG Lup, V526 Sgr and AO Vel
Several new times of minimum light have been observed photoelectricalyfor the early-type double-lined eccentric eclipsing binaries V539 Ara (P= 3.2 deg, e = 0.05), GG Lup (1.9 deg, 0.15), V526 Sgr (1.9 deg, 0.22)and AO Vel (1.6 deg, 0.07). The O{-}C diagrams are analysed using allreliable timings found in the literature and improved values for theelements of the apsidal motion are computed. We find more precise,relatively short periods of apsidal motion of about 162, 102, 155 and 54years for V539 Ara, GG Lup, V526 Sgr and AO Vel, respectively. Thecorresponding internal structure constants, log k_2, are then found tobe 2.33, 2.16, 2.36 and 2.24 under the assumption that the componentstars rotate pseudosynchronously. The relativistic effects arenegligible, being about 6 7% of the total apsidal motion rate in allsystems. Using the light-time effect solution, for V539 Ara we havefound a third component orbiting with a period of about 42 years, for AOVel we confirmed the third body with an orbital period of 33 years.
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Beobachtungssergebnisse Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V.
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Apsidal Motion in Detached Binary Stars: Comparison of Theory and Observations
A list of 62 detached binaries having reliable data on the rotation ofthe line of apsides is considered. Theoretical estimates of the rate ofapsidal motion are obtained. These estimates are compared withobservational data. It is shown that cases in which the theoreticalestimate exceeds the observed value are several times more frequent thancases in which the theoretical value is lower than the observed one.This discrepancy increases when systems with more reliable observationaldata are considered.
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149 Bedeckungssterne der BAV-Programme. Eine Analyse der Beobachtungstatigkeit seit den Angangen.
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Das Brunner Punktesystem.
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Apsidal Motion in Double Stars. I. Catalog
A catalog of 128 double stars with measured periods of apsidal motion iscompiled. Besides the apsidal periods, the orbital elements of binariesand physical parameters of components (masses, radii, effectivetemperatures, surface gravities) are given. The agreement of the apsidalperiods found by various authors is discussed.
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Orbital circularization in detached binaries with early-type primaries
Extending our previous study, the present paper reports on thediscussion of the orbital circularization in 37 detached binaries withearly-type primaries. From comparison of the theoretical predictionswith the orbital eccentricities of our binary systems, we find thatZahn's circularization theories are substantially consistent with theobserved data for overwhelming majority of our samples. However, we alsonote that three binaries of whom both components are asynchronizedrotators possess circular orbits. How to understand the circularism ofthe three systems remains a problem not only to Zahn's theories, but toall other present circularization mechanisms.We think that studies onthe circularization of pre-main-sequence binary systems could providesome clues for the problem.
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The apsidal motion test of stellar structure in relativistic systems.
We have compared observational data of apsidal motion rates forrelativistic eclipsing binaries with theoretical predictions based onstellar theoretical models. Ten double-lined eclipsing binaries withhigh quality light curves and radial velocities were selected. Theanalysis of the data available indicate that the predictions by theGeneral Relativity and the new stellar models are able to explain theshift in the periastron position. The two versions of thenon-symmetrical theory of gravitation were also investigated. The earlyversion of this theory (Moffat, 1984ApJ...287L..77M) is not supportedwhen contrasted with recent observational data since it predicts tooslow apsidal motion rates. The more recent version (Moffat,1989PhRvD..39..474M) presents several problems in its formulation, liketoo many degrees of freedom and some parameters for which there is nosevere physical constraint. Moreover, such a theory is not able topredict a priori the apsidal motion rates.
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Synchronization in the early-type detached binary stars.
With a set of homogeneous and refined rotational velocities, we discussthe synchronism in the "normal" (all the particular stars, such as Ap,Am and Of, are excluded) early-type detached binaries. Being differentfrom previous statistical studies, the present paper not onlyinvestigates the rotational synchronism of each component, but alsoestimates its age from new stellar evolutionary grids, and calculatesits synchronization time scale with Zahn's dynamically tidal theory.Significantly, we find that the dynamically tidal synchronizationmechanism is substantially compatible with the observed data from thecomparison of the rotational properties of our components with thetheoretical predictions.
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Measurement and study of rotation in close binary stars. (V) Orbital circularization.
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Photoelectric minima of 30 eclipsing binary systems
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Measurement and study of rotation in close binary stars (IV) Comparison between observation and predictions of two theories.
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Measurement and study of rotation in close binary stars (III) Statistical analysis of synchronization.
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Measurement and analysis of rotation in close binaries. II. Calculation of synchronism.
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Eclipse Monitoring of Eccentric Binary Systems
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Predicting the Secondary Minima Depths and Spectra of the Main Components for the Dm-Type Eclipsing Variable Stars
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UBV photometry of selected eclipsing binary stars
The study reports new UBV observations of 69 eclipsing binary stars andprovides outside-eclipse averages. Revised photometric properties offive of the binaries, for which absolute properties were publishedpreviously, are computed. Comparisons are made with previous photometry,when available, and notes are given for some individual systems.
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Eclipsing binaries with eccentric orbits
Two groups of eclipsing binaries are dealt with: the first consists ofall binaries with enough data in the General Catalog of Variable Stars(GCVS; Cholopov et al, 1987), the other of those for which accurateparameters are known. In the first group, problems with classificationin GCVS are noticed and several examples of binaries with unexpectedparameters are named. For binaries of the second group, their fractionalradii, ages, and initial radii are used to discuss the relation of theirevolutionary status and orbital eccentricity. Dependence of eccentricityon spectral type and age is observed, and no peak in the initialeccentricity distribution at e = 0 seems to be present. It is suggestedthat binary origin by fragmentation followed by disruption of initialmultiple systems can explain all observed binaries, perhaps with theexception of contact systems in the main sequence. In several cases thecircularization must be due to mass transfer in the eccentric orbit.
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Photometric study of the V889 AQL eclipsing binary system with relativistic orbital rotation
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Some remarks on eclipsing binaries seeming to be inconsistent with general relativity
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An Updated List of Eclipsing Binaries Showing Apsidal Motion
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On the Relativistic Apsidal Motion in the Eclipsing System V889-AQUILAE
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The Third Body in Eclipsing Binary System V889-AQUILAE
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Eclipsing Binaries - Andromeda to Camelopardalis in 1972-1983
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General-relativistic periastron advances in eclipsing binary systems
The possibility of observing general-relativistic apsidal motionsoutside the solar system in well-detached eclipsing binaries isreviewed, taking into account the expected influence of the variousparameters involved. A procedure to select candidate systems amongeccentric eclipsing binaries is presented altogether with a list ofsuggested targets. A simplified method to obtain the apsidal motionrates from the observation of times of minimum light is proposed.
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The orbital motion of DI Herculis as a test of a theory of gravitation
The eclipsing binary system DI Her has been observed to have a smallrate of motion of the periastron during a period of more the 80 years.This disagrees with the predictions of Newtonian theory and generalrelativity by a large amount (21 sigma). The nonsymmetric gravitationaltheory can explain this observational result. The observed periastronmotions of several other binary systems are also fitted by the theory.
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The period distribution of unevolved close binary systems
Period distributions have been examined for various spectral types ofabout 600 (eclipsing and spectroscopic) close binaries, which are likelyto be substantially unevolved. The comparison with the previouscorresponding analyses of extensive (but heterogeneous) binary samplesallows a clarification of the extent of the evolutionary andobservational selection effects. Remarkably, this analysis reveals agreat deficiency of short period binaries (with periods corresponding tocase A mass transfer) in the whole spectral range. For the late spectraltypes, this result may be connected with postformation angular momentumloss caused by stellar wind magnetic braking; at least for the late Band A spectral range, a ready interpretation of this finding is thatclose binaries of corresponding periods and spectral types are rarelyformed.
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Statistics of categorized eclipsing binary systems Lightcurve shapes, periods, and spectral types
The statistics of the light curve morphologies, eclipse depths, orbitalperiods, and spectral types of about 1000 eclipsing binary systems areexamined, after attempting to subdivide these binaries into variousbasic evolutionary categories. The applicability of statisticalcriteria, based on light curve morphologies and eclipse depths, for thecategorization of eclipsing binaries has been found more limited thanpreviously believed. In particular, EW-type light curves turn out to begood indicators of contact systems (though not conversely), while EA-and EB-type light curves have little physical significance. Moreover,the study reveals a strong deficit of short-period noncontact systems inthe whole spectral range, together with an underabundance of early-typecontact binaries (compared with the number of late-type contact pairs).Interestingly, the distribution of evolved Algol-type systems isshifted, on average, to periods longer than those of unevolved detachedsystems in the OB and early A spectral range (and to shorter periods inthe F spectral range).
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