Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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New Times of Minima of Eclipsing Binary Systems
We present 82 photoelectric minima observations of 34 eclipsingbinaries.
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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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Apsidal motion and the third-body problem in the binary HS Her
Our analysis of a 22-year uniform series of photoelectric U BVmeasurements of HS Her, started in 1969 1983 by D.Ya. Martynov andcompleted by us in 1984 1991, enabled us to determine new times ofminima and revise some times of minima published earlier. Combined withother published data, this information can be used to improve thesystem’s apsidal elements: U obs = (89.7 ± 5.1) years andlog-k 2 obs = -2.33(4), testifying to a somewhat stronger concentrationof matter towards the center than is predicted by current models formain-sequence stars (log -k 2 th = -2.21). This provides additionalevidence that the system’s secondary is at the pre-main-sequencestage of evolution, as we suggested earlier based on our analysis of thesystem’s photometric elements. We confirm the presence of a thirdbody in the system in a long-period eccentric orbit, as was firstsuggested in 2002 by Wolf et al. However, in contrast to the results ofthat paper, we demonstrate that the currently available observationaldata are insufficient to reliably determine this orbit’sparameters. We estimate the mass of the third body to be M 3 =(1.0-2.0)M ȯ for M 1 = 5M ȯ and M 2 = 1.6 M ȯ.
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The eclipsing binary HS hercules: Photometric elements and the evolutionary stages of its components
We used a photoelectric photometer designed by V.M. Lyutyi and theZeiss-600 telescope of the Sternberg Astronomical Institute’sCrimean Observatory to acquire precise UBV brightness measurements(σ obs V 0.007m) for the eclipsing binary system HS Her in1984 1991. These measurements continue the homogeneous series ofobservations of this star commenced in 1969 by D.Ya. Martynov using thesame equipment. Our detailed analysis of this homogeneous 22-year seriesof photoelectric observations has yielded a self-consistent set ofphysical and geometric parameters of the binary, and enabled us toestablish the evolutionary stages of its components. The systems’sprimary, M 1 = 5 M ȯ, is at the beginning of its main-sequenceevolution, whereas its secondary, M 2 = 1.6 M ȯ, has not yetreached the main sequence. The binary’s age is estimated to be t =(17 ± 3) × 106 years.
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New Times of Minima of Eclipsing Binary Systems and of Maximum of SXPHE Type Stars
We present 64 photoelectric minima observations of 31 eclipsingbinaries. We also report three new times of maxima of three SXPHE typepulsating stars.
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Evolution of interacting binaries with a B type primary at birth
We revisited the analytical expression for the mass ratio distributionfor non-evolved binaries with a B type primary. Selection effectsgoverning the observations were taken into account in order to comparetheory with observations. Theory was optimized so as to fit best withthe observed q-distribution of SB1s and SB2s. The accuracy of thistheoretical mass ratio distribution function is severely hindered by theuncertainties on the observations. We present a library of evolutionarycomputations for binaries with a B type primary at birth. Some liberalcomputations including loss of mass and angular momentum during binaryevolution are added to an extensive grid of conservative calculations.Our computations are compared statistically to the observeddistributions of orbital periods and mass ratios of Algols. ConservativeRoche Lobe Over Flow (RLOF) reproduces the observed distribution oforbital periods but fails to explain the observed mass ratios in therange q in [0.4-1]. In order to obtain a better fit the binaries have tolose a significant amount of matter, without losing much angularmomentum.
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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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Photoelectric Minima of Some Eclipsing Binary Stars
We present 70 minima times of 35 eclipsing binaries.
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There is No Third Body in the Eclipsing Binary System HS Herculis
We present a complete period analysis of eclipsing binary system HSHerculis. In order to increase the number of minimum times, we observedfive new minima in 2002 and 2003. Using all available minimum times, weanalyzed the O-C diagram of HS Her and we confirmed an apsidal motionwith a period of about 77 years. According to the results of thedetailed analysis, we determined that there is no third body in thesystem and the O-C curve can be explained with only apsidal motion.
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Aus den IBVS.
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Catalogue of Algol type binary stars
A catalogue of (411) Algol-type (semi-detached) binary stars ispresented in the form of five separate tables of information. Thecatalogue has developed from an earlier version by including more recentinformation and an improved layout. A sixth table lists (1872) candidateAlgols, about which fewer details are known at present. Some issuesrelating to the classification and interpretation of Algol-like binariesare also discussed.Catalogue is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/417/263
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Apsidal Motion in Binaries: Rotation of the Components
A sample of 51 separated binary systems with measured apsidal periodsand rotational velocities of the components is examined. The ranges ofthe angles of inclination of the equatorial planes of the components tothe orbital plane are estimated for these systems. The observed apsidalvelocities can be explained by assuming that the axes of rotation of thestars are nonorthogonal to the orbital plane in roughly 47% of thesystems (24 of the 51) and the rotation of the components is notsynchronized with the orbital motion in roughly 59% of the systems (30of 51). Nonorthogonality and nonsynchrony are defined as deviations from90° and a synchronized angular velocity, respectively, at levels of1 or more.
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New Times of Minima of Eclipsing Binary Systems
We present several photoelectric minima observations of 15 eclipsingbinaries.
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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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Apsidal motion and light-time effect in eclipsing binaries HS Herculis and U Ophiuchi
Several new times of minima, based on photoelectric observations, havebeen secured for two bright and well-known eclipsing binaries witheccentric orbits and with very similar orbital periods: HS Her (P =1fd637 , e = 0.02) and U Oph (P = 1fd677 , e = 0.003). For HS Her, anapsidal motion with a period of 78 years is confirmed and a third bodyin an eccentric orbit with a period of 85 years is found. An analysis ofall available eclipse timings of U Oph has confirmed the presence of anapsidal motion with one of the shortest known periods (20.1 yr) and alight-time effect with the improved period of 37.6 yr. The correspondinginternal structure constants log k2 were also derived. It isestimated that the tertiaries of both systems are detectable via speckleinterferometry. Partly based on photoelectric observations secured atthe San Pedro Mártir Observatory, Baja California, Mexico.
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Apsidal motion in eccentric eclipsing binaries: TV Ceti and V451 Ophiuchi
Several new times of minimum light recorded with photoelectric meanshave been gathered for two bright eccentric eclipsing binaries TV Cet (P= 9fd1 , e = 0.055) and V451 Oph (P = 2fd2 , e = 0.013). Analysis of allavailable eclipse timings of TV Ceti has revealed a small motion of theline of apsides of dot ω = 0.000 30 +/- 0.000 08 degcycle-1, corresponding to an apsidal period of U = 30 000 +/-8 000 years. The contribution from the general relativity effects isdominant (dot ωrel/dot ω ~ 80 % ). In thissystem, the third body on an eccentric orbit with a period of 28.5 yearsis also predicted. The more precise values for the apsidal motionelements were computed for V451 Oph, where apsidal motion with a periodof 170 +/- 5 years was confirmed. The corresponding internal structureconstants log k2 were derived. Some of the observationsreported in this paper were obtained at the South Africa AstronomicalObservatory, Sutherland, South Africa.
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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
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CCD Times of Minima of Eclipsing Binary Systems
We present several CCD minima observations of 22 eclipsing binaries.
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Photoelectric Minima of Selected Eclipsing Binaries
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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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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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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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The calculation of critical rotational periods in three typical close binary systems based on synchronization theory.
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Measurement and study of rotation in close binary stars. (V) Orbital circularization.
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Photoelectric Minima of Selected Eclipsing Binaries
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Photoelectric Minima of Some Eclipsing Binaries
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Photoelectric minima of 30 eclipsing binary systems
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