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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.
| Beobachtungssergebnisse Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V.
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| Modeling the Eclipsing Binary System VW Cygni
Five color UBVRI photometric and polarimetric measurements of theeclipsing binary VW Cyg are reported. It is shown that in the primaryminimum the luminosity is attenuated (at short wavelengths) even afterpassage of the second contact. This fact is interpreted as evidence ofgaseous structures in the system. The exchange of matter among thesystem components is also confirmed by the O-C curve constructed fromdata covering nearly a hundred years. Polarimetric analysis makes itpossible to isolate the intrinsic (P=0.030±0.02) and interstellarcomponents of the polarization. The UBVRI light curves of VW Cyg havebeen resolved. This was done using an algorithm for synthesizingtheoretical light curves in the Roche model. Good agreement was obtainedbetween the theoretical curves and observations in the V, R, and Ibands, but the observed minimum depths in the U and B bands exceed thetheoretical values. This appears to be caused by gas flows in thesystem.
| 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
| Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veranderlichen Serne e.V.
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| Beobachtungsegebnisse Bundesdeutsche Arbeitsgemainschaft fur Veranderliche Sterne e.V.
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| Einige interessante Bedeckungsveraenderliche.
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| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| A Search for Trojan Extrasolar Planets: Planets in V442 Cas and YZ Aql?
In this project we are exploring the light curves of eclipsing binariesfor the signature of planets that may exist at the L4 and L5 Lagrangepoints of the stellar system. While no binaries are known to exist thatstrictly satisfy the stellar mass ratio constraint for the restrictedthree-body problem, the general solution would allow a planet formed atthe L-point to remain there if there are no major perturbing bodies suchas an additional planet. We have coined such objects "Trojan planets."The advantage of this approach is that the phases of the planetaryeclipses are known. We picked systems with deep primary eclipses, tomaximize the amount of system light eclipsed by the planet when in frontof the hotter star. We also scanned the Finding List for Observers ofInteractive Binary Stars, for G dwarf systems ,but found only a few thatwere high inclination and detached. The target list includes QY Aql, YZAql, V442 Cas, SS Cet, S Cnc, VW Cyg, WW Cyg, RR Dra, RX Gem, RY Gem, VWHya, Y Leo, TV Mon, BN Sct, UW Vir, AC UMa, TX UMa, and GSC 1657. Wehave concentrated on V442 Cas and YZ Aql, based on initial results thatshow anomalies in the light curves near the phases where a Trojan planeteclipse is expected. We present results on these two, as well as initialresults for some of the other systems. We gratefully acknowledge thesupport of the National Science Foundation, through grants AST-9731062and AST-0089248. We also appreciate the support of the Fund forAstrophysical Research. Gregory Shelton and Brenda Corbin, at the U.S.naval Observatory Library, have been indispensable in providingreferences for these binary systems. This research has made use of theSimbad database, operated at CDS, Strasbourg, France
| Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
| TRY Geminorum - Revised Elements
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114..800S&db_key=AST
| GSC1657.1754: a New Deeply Eclipsing Binary System in Delphinus
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| Catalogue of stars in the northern Milky Way having H-alpha in emission
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| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
| New rotational velocities for eclipsing binaries, and a comparison of spectroscopic and photometric rotations
Rotational velocities are determined spectroscopically for 38 eclipsingbinaries, including many long-period, nominally semidetached, systems.We note that spectroscopic rotations may differ from rotations derivedfrom light-curve modeling using the Wilson-Devinney program. In'direct-impact' mass-transferring systems, or in most systems withperiods smaller than about 7 days, observations suggest that the tworotations are usually about the same. In cases where the stream missesthe gainer and an accretion disk forms, however, photometric rotationestimates often exceed spectroscopic determinations. The possiblephysical significance of this situation is briefly discussed. Doubt iscast on the likelihood that the rotation of the hot component of U Sgehas changed detectably in the last 30 years.
| The fractional dimensions of close binary systems components: the reliability of their determination
The accuracy of determining the fractional dimensions of close binarysystems is analysed. The analysis is based on the catalogue of modernlightcurve synthesis photometric solutions of close binary systems. Onlya small percentage of the fractional dimensions is derived with anaccuracy attainable by using photoelectric photometry and modernlightcurve synthesis methods. The sources of the inaccuracy arediscussed and some recommendations for improvement are given.
| Gravitational radiation and spiralling time of close binary systems (V)
Forty-six binary systems with their primary component masses between 2and 3 solar masses have been considered for gravitational radiationstudy. Power output by gravitational radiation (PB) and spiral timetau(0) for all individual systems have been evaluated. A relation hasbeen given between PB and tau(0). The rate of decrease of orbital periodhas also been given for 10 eccentric orbit systems.
| Statistical study of semi-detached and near-contact semi-detached binaries
A statistical study was made of 107 semidetached with combined lightcurve solutions. An empirical period-dependent mass-radius relation wasderived, thereby revealing the impossibility of having evolvedsemidetached systems with very short periods. Statistically, thenear-contact semidetached systems have the common properties of nearlyequal mass densities of the components, larger mass-ratios, shorterperiods and smaller specific angular momenta, and their A- F-typesecondaries generally have greater densities than the secondaries ofclassical Algol systems of the same spectral types. A detaileddiscussion is also made in this paper on the evolution of near-contactsemidetached binaries.
| Fourier analysis of the light changes of eclipsing variables in the frequency-domain
The method of Fourier analysis of the light changes in thefrequency-domain has been studied and discussed for 92 light curves ofdifferent types of eclipsing binary systems. Geometrical and physicalelements of the systems under analysis have been listed and discussed;accordingly the advantages and disadvantages of the method arepresented. The results show that the method is suitable for the analysisof detached and most of the semidetached systems, while for contactbinaries and Beta-Lyrae-type stars it has some difficulties. The lightcurve synthesis method is recommended.
| Statistical Study on the Semidetached and Near Contact Semidetached Binary Systems
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| Eclipsing binaries, Cygnus to Hydra, in 1972-1985
Photoelectric and visual observations of 40 known and suspectedeclipsing binaries are discussed. Revised light elements are derived forthree systems. The period of V450 Her should possibly be doubled fromabout 0.9d to about 1.8d. Secondary minimum has been detected in DI Hya.
| Absolute parameters of stars in semidetached eclipsing binary systems
A number of questions concerning the absolute parameters of stars insemidetached binary systems are addressed. Consideration is given to:similarities between Algol-type binaries and unevolved detached binarieswith respect to the mass-luminosity law; and the single-line classicalAlgol candidates with known mass functions and photometric solutions formass ratio. It is shown that the validity of the mass luminosity-lawcannot be verified for individual Algol-type binaries though it doeshold well on average; and (2), the existence of a definite class ofsd-binaries not containing a proportion of significantly undersize typesis apparent. The conclusions are found to be in general agreement withthe observations of Hall and Neff (1979).
| A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
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| Revised elements and evolutionary status of six eclipsing binary stars
Twelve photoelectric light curves of six eclipsing binary stars namelyGG Cas, WX Cep, UZ Cyg, VW Cyg, AQ Peg and ST Per in two differentfilters (B and V for the first five binaries and R and I for ST Per)have been analysed by Kopal's new method of analysis of the light curvesof eclipsing system in the frequency domain. The elements of the systemshave been evaluated and their evolutionary status discussed.
| A study of the O'Connell effect in the light curves of eclipsing binaries
In the present consideration of O'Connell's (1951) study of the lightcurve asymmetry between outside eclipse maxima, using UBV photoelectricdata, parametric and nonparametric methods indicate significantcorrelations in at least one color between the size of the asymmetry, onthe one hand, and several additional parameters. These include: thecolor index of the asymmetry, the relative sizes of the hotter andsmaller components, and their distortion, the relative separation of thestars, and the logarithm of the period. The present study data arecharacterized by lower mean amplitudes and a much more even distributionof the asymmetry, with respect to sign, than that of O'Connell, andthere is a tendency for the brighter maximum to be redder, contrary toO'Connell's results. More than one mechanism for the O'Connell effect issuggested.
| Fourier analysis of the light changes of four Algol-type eclipsing variables
An analysis of the light curves of four totally-eclipsing systems (BMOri VW Cyg, TW Dra, and RW Mon) is presented, based on the automatedFourier techniques in the frequency domain developed by Kopal (1982).The physical and geometrical elements of the systems are derived. Theresults are found to be in good agreement with similar results forgeometric elements recently quoted in the literature. It is concludedthat the method applies for the case of deep primary minima, but doesnot apply well to secondary minima. The views of the three systems, RWMon, TW Dra, and VW Cyg are compatible with the current observationaldata concerning Algol-type binaries. The age of the Trapezium in thesesystems is only 100,000 years old.
| 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).
| Revised photometric elements of three semi-detached binary systems
It is found through analysis of the V and B light curves of the UZ Cyg,VW Cyg and AQ Peg Algol-type eclipsing binaries by the Wilson andDevinney (1971) model that all are semi-attached systems, with A-typeprimary components and K-type evolved secondary which fill thecorresponding lobe. Only VW Cyg may alternatively be considered an sd-dsystem. The computing procedures employed have been described byMaceroni et al, (1981) and Milano et al (1981b).
| Some aspects of mass loss and mass transfer in Algol variables
Algol variables are examined to clarify evolutionary implications, andcheck the validity of simple models of nonconservative mass transfer.Properties of Algol variables, including the distribution of mass,radii, mass ratios, and orbital periods, are compared with statisticalanalyses of eclipsing and spectroscopic binaries. Results indicate thatas the total mass of the Algol system increases, the orbital perioddecreases, the mass ratio increases, and the secondary components becomeless prominent. Initial values of orbital periods and total mass areestimated and calculated according to conservative assumptions, althoughthe evolutionary status of 20 percent of the Algol variables could notbe accounted for using these calculations. Relatively large mass andangular momentum loss is found in several Algol variables, and case Bmass exchange is so strongly favored for variables of relatively lowmass, that no candidate for products of case A mass transfer exists.Case A is found to predominate for variables of higher total mass,although not as strongly as expected, and thus a large deficit of case Aremnant systems is observed.
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| קבוצת-כוכבים: | ברבור |
| התרוממות ימנית: | 20h15m12.29s |
| סירוב: | +34°30'48.3" |
| גודל גלוי: | 10.275 |
| תנועה נכונה: | 7 |
| תנועה נכונה: | -2.3 |
| B-T magnitude: | 10.648 |
| V-T magnitude: | 10.306 |
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