B.R.N.O. Contributions #34
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A new catalogue of eclipsing binary stars with eccentric orbits
A new catalogue of eclipsing binary stars with eccentric orbits ispresented. The catalogue lists the physical parameters (includingapsidal motion parameters) of 124 eclipsing binaries with eccentricorbits. In addition, the catalogue also contains a list of 150 candidatesystems, about which not much is known at present.Full version of the catalogue is available online (see the SupplementaryMaterial section at the end of this paper) and in electronic form at theCDS via http://cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/MNRAS/(vol)/ (page)E-mail: ibulut@comu.edu.tr
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Die BAV-Zusammenarbeit zwischen Fachastronomen und Amateuren.
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CCD Times of Minima of Selected Eclipsing Binaries
374 CCD minima observations of 187 eclipsing binaries are presented. Theobserved stars were chosen mainly from catalogue BRKA of observingprogramme of Variable Star Section of CAS.
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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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A catalogue of close binaries located in the δ Scuti region of the Cepheid instability strip
A catalogue of close eclipsing binary systems (detached andsemidetached) with at least one of the components located in the δScuti region of the Cepheid instability strip is presented. Thepositions of the stars in the instability strip are determined by theiraccurate temperatures and luminosities. Observationally detectedbinaries (20 semidetached, four detached and one unclassified) withoscillating components were included in the catalogue as a separatetable. The primaries of the oscillating Algols tend to be located nearthe blue edge of the instability strip. Using reliable luminosities andtemperatures determined by recent photometric and spectroscopic studies,we have found that at least one or two components of 71 detached and 90semidetached systems are located in the δ Scuti region of theCepheid instability strip. In addition, 36 detached or semidetachedsystems discovered by the Hipparcos satellite were also given as aseparate list. One of their components is seen in the δ Scutiregion, according to their spectral type or B - V colours. They arepotential candidate binaries with the δ Scuti-type pulsatingcomponents which need further photometric and spectroscopic studies inbetter precision. This catalogue covers information and literaturereferences for 25 known and 197 candidate binaries with pulsatingcomponents.
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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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Absolute dimensions of detached eclipsing binaries - I. The metallic-lined system WW Aurigae
WW Aurigae is a detached eclipsing binary composed of two metallic-linedA-type stars orbiting each other every 2.5 d. We have determined themasses and radii of both components to accuracies of 0.4 and 0.6 percent, respectively. From a cross-correlation analysis of high-resolutionspectra we find masses of 1.964 +/- 0.007 Msolar for theprimary star and 1.814 +/- 0.007 Msolar for the secondarystar. From an analysis of photoelectric uvby and UBV light curves wefind the radii of the stars to be 1.927 +/- 0.011 Rsolar and1.841 +/- 0.011 Rsolar, where the uncertainties have beencalculated using a Monte Carlo algorithm. Fundamental effectivetemperatures of the two stars have been derived, using the Hipparcosparallax of WW Aur and published ultraviolet, optical and infraredfluxes; these are 7960 +/- 420 and 7670 +/- 410 K. The masses, radii andeffective temperatures of WW Aur are only matched by theoreticalevolutionary models for a fractional initial metal abundance, Z, ofapproximately 0.06 and an age of roughly 90 Myr. This seems to be thehighest metal abundance inferred for a well-studied detached eclipsingbinary, but we find no evidence that it is related to the metallic-linednature of the stars. The circular orbit of WW Aur is in conflict withthe circularization time-scales of both the Tassoul and the Zahn tidaltheories and we suggest that this is due to pre-main-sequence evolutionor the presence of a circular orbit when the stars were formed.
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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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Photoelectric Minimum Times of Some Eclipsing Binary Stars
We present 20 minima times of 8 eclipsing binaries.
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uvbyβ Photometry of Selected Eclipsing Binary Stars
New uvbyβ observations of 51 eclipsing binary stars are presented,and outside-eclipse averages for 45 of them are given. Many of thesebinaries are detached main-sequence pairs that have been discovered tobe double-lined spectroscopic binaries and appear suitable fordeterminations of accurate absolute dimensions and masses. Photometricproperties are recomputed for 14 of the binaries, for which absoluteproperties have been published previously. Intercomparisons are madewith previous photometry, when available, and notes are given for someindividual systems.
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New results on the apsidal-motion test to stellar structure and evolution including the effects of dynamic tides
We revised the current status of the apsidal-motion test to stellarstructure and evolution. The observational sample was increased by about50% in comparison to previous studies. Classical and relativisticsystems were analyzed simultaneously and only systems with accurateabsolute dimensions were considered. New interior models incorporatingrecent opacity tables, stellar rotation, mass loss, and moderate coreovershooting were used as theoretical tools to compare the predictedwith the observed shifts of the position of the periastron. The stellarmodels were computed for the precise observed masses and the adoptedchemical compositions are consistent with the corresponding tables ofopacities to avoid the inherent problems of interpolation in mass and in(X, Z). The derived chemical composition for each individual system wasused to infer the primordial helium content as well as a law ofenrichment. The values found are in good agreement with those obtainedfrom various independent sources. For the first time, the effects ofdynamic tides are taken into account systematically to determine thecontribution of the tidal distortion to the predicted apsidal-motionrate. The deviations between the apsidal-motion rates resulting from theclassical formula and those determined by taking into account theeffects of dynamic tides are presented as a function of the level ofsynchronism. For systems close to synchronisation, dynamic tides causedeviations with respect to the classical apsidal-motion formula due tothe effects of the compressibility of the stellar fluid. For systemswith higher rotational angular velocities, additional deviations due toresonances arise when the forcing frequencies of the dynamic tides comeinto the range of the free oscillation modes of the component stars. Theresulting comparison shows a good agreement between the observed andtheoretical apsidal-motion rates. No systematic effects in the sensethat models are less mass concentrated than real stars and nocorrelations with the evolutionary status of the systems were detected.
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149 Bedeckungssterne der BAV-Programme. Eine Analyse der Beobachtungstatigkeit seit den Angangen.
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Bedeckungsveraenderliche mit Apsidendrehung.
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Das Brunner Punktesystem.
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Speckle Interferometry of New and Problem Hipparcos Binaries. II. Observations Obtained in 1998-1999 from McDonald Observatory
The Hipparcos satellite made measurements of over 9734 known doublestars, 3406 new double stars, and 11,687 unresolved but possible doublestars. The high angular resolution afforded by speckle interferometrymakes it an efficient means to confirm these systems from the ground,which were first discovered from space. Because of its coverage of adifferent region of angular separation-magnitude difference(ρ-Δm) space, speckle interferometry also holds promise toascertain the duplicity of the unresolved Hipparcos ``problem'' stars.Presented are observations of 116 new Hipparcos double stars and 469Hipparcos ``problem stars,'' as well as 238 measures of other doublestars and 246 other high-quality nondetections. Included in these areobservations of double stars listed in the Tycho-2 Catalogue andpossible grid stars for the Space Interferometry Mission.
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Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
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Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veraenderliche Sterne e.V.
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Absolute Dimensions of the Unevolved B-Type Eclipsing Binary GG Orionis
We present photometric observations in B and V, as well as spectroscopicobservations of the detached, eccentric 6.6 day double-lined eclipsingbinary GG Ori, a member of the Orion OB1 association. Absolutedimensions of the components, which are virtually identical, aredetermined to high accuracy (better than 1% in the masses and betterthan 2% in the radii) for the purpose of testing various aspects oftheoretical modeling. We obtain MA=2.342+/-0.016Msolar and RA=1.852+/-0.025 Rsolar forthe primary, and MB=2.338+/-0.017 Msolar andRB=1.830+/-0.025 Rsolar for the secondary. Theeffective temperature of both stars is 9950+/-200 K, corresponding to aspectral type of B9.5. GG Ori is very close to the zero-age mainsequence, and comparison with current stellar evolution models givesages of 65-82 Myr or 7.7 Myr, depending on whether the system isconsidered to be burning hydrogen on the main sequence or still in thefinal stages of pre-main-sequence contraction. Good agreement is foundin both scenarios for a composition close to solar. We have detectedapsidal motion in the binary at a rate of ω=0.00061d+/-0.00025dcycle-1, corresponding to an apsidal period ofU=10,700+/-4500 yr. A substantial fraction of this (~70%) is due to thecontribution from general relativity, and our measurement is entirelyconsistent with theory. The eccentric orbit of GG Ori is well explainedby tidal evolution models, but both theory and our measurements of therotational velocity of the components are as yet inconclusive as towhether the stars are synchronized with the orbital motion. Some of theobservations reported here were obtained with the Multiple MirrorTelescope, a joint facility of the Smithsonian Institution and theUniversity of Arizona.
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Absolute Dimensions of the A-Type Eclipsing Binary V364 Lacertae
We present photoelectric observations in B and V, as well asspectroscopic observations of the 7.3 day period double-lined eclipsingbinary V364 Lacertae. From the analysis of the light curves and theradial velocity curves we have determined the absolute dimensions of thecomponents with high precision (<~1%). The masses for the primary andsecondary are M_A=2.333+/-0.015 M_solar and M_B=2.296+/-0.025 M_solar,respectively, and the radii are R_A=3.307+/-0.038 R_solar andR_B=2.985+/-0.035 R_solar. We derive also effective temperatures ofT^A_eff=8250+/-150 K and T^B_eff=8500+/-150 K, and projected rotationalvelocities of v_Asini=45+/-1 km s^-1 and v_Bsini=15+/-1 km s^-1.Evolutionary tracks from current stellar evolution models are in goodagreement with the observations for a system age of logt=8.792 (6.2x10^8yr) and for solar metallicity. Hints of a lower metallicity fromspectroscopy and photometry appear to be ruled out by these models, buta definitive comparison must await a more accurate spectroscopicabundance determination. Analysis of all available eclipse timings alongwith our radial velocities of this moderately eccentric system(e=0.2873+/-0.0014) has revealed a small but significant motion of theline of apsides of ω=0.00258+/-0.00033 deg cycle^-1, correspondingto an apsidal period of U=2810+/-360 yr. The contribution from generalrelativity effects is significant (~17%). A comparison with predictionsfrom interior structure models shows the real stars to be lessconcentrated in mass than expected. Our measurements of the projectedrotational velocities indicate that the primary star is essentiallypseudosynchronized (synchronized at periastron), while the secondary isspinning 3 times more slowly and is not yet synchronized. Both therotational status of the stars and the nonzero eccentricity of the orbitare consistent with the predictions from tidal theory, specifically forthe radiative damping mechanism.
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Photoelectric Minima of Selected Eclipsing Binaries
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Times of Minima of Eclipsing Binaries
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Photoelectric Minima and Maxima of Selected Eclipsing and Pulsating Variables
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Times of Minima of Eight Eclipsing Binaries
We report times of minima of eccentric eclipsing binaries derived fromphotometric observations made at Ege University Observatory in Turkeyand at Cerro Tololo Interamerican Observatory (CTIO) in Johnson B and Vfilters, and at the High Altitude Maidanak Observatory in Uzbekistan inJohnson U,B,V,R filters. Heliocentric times of minimum were estimatedfor each filter by using the method of Kwee and Van Woerden (1956) asadapted to a Macintosh computer. The adopted time of minimum was thenthe average over all filters. In all cases the times of minimum indifferent filters was concordant. Uncertainties in the times of minimawere estimated from the values of standard error computed by the methodand from the differences in times derived from the various filters used.Primary eclipses are designated as type 1 eclipses, and secondaryeclipses as type 2.
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Eclipse Monitoring of Eccentric Binary Systems
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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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Optical behaviour of the X-ray binary V1727 Cygni = 4U 2129+47 in the season 1988/1989.
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An Updated List of Eclipsing Binaries Showing Apsidal Motion
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Beobachtungsergebnisse des Arbeitskreises "Veranderliche Sterne" im Kulturbund der DDR (Teil XIII).
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New Double-Lined Eclipsing Binaries Found with RETICON, Digicon, and CCD Detectors
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INHABITED SKY
