Analysis of Van Houten's Estimates of Variable Stars From Photographic Plates
Huge amount of observations from photogrphic plates made by C. J. vanHouten remained unprocessed and unpublished after his death. The datawere obtained during the first half of the 20th century. All of thestars are situated on the southern hemisphere a most of them areeclipsing binaries. These times of minima can do a great job for O-Canalysis of these objects. The aim of this paper is to introduce thisproject.
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New CCD Times of Minima of Eclipsing Binary Systems
We present a total of 208 CCD timings for 103 eclipsing binaries.
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Automatic classification of eclipsing binaries light curves using neural networks
In this work we present a system for the automatic classification of thelight curves of eclipsing binaries. This system is based on aclassification scheme that aims to separate eclipsing binary systemsaccording to their geometrical configuration in a modified version ofthe traditional classification scheme. The classification is performedby a Bayesian ensemble of neural networks trained with Hipparcos data ofseven different categories including eccentric binary systems and twotypes of pulsating light curve morphologies.
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On the properties of contact binary stars
We have compiled a catalogue of light curve solutions of contact binarystars. It contains the results of 159 light curve solutions. Theproperties of contact binary stars were studied using the cataloguedata. As is well known since Lucy's (\cite{Lucy68a},b) and Mochnacki's(\cite{Mochnacki81}) studies, primary components transfer their ownenergy to the secondary star via the common envelope around the twostars. This transfer was parameterized by a transfer parameter (ratio ofthe observed and intrinsic luminosities of the primary star). We provethat this transfer parameter is a simple function of the mass andluminosity ratios. We introduced a new type of contact binary stars: Hsubtype systems which have a large mass ratio (q>0.72). These systemsshow behaviour in the luminosity ratio- transfer parameter diagram thatis very different from that of other systems and according to ourresults the energy transfer rate is less efficient in them than in othertypes of contact binary stars. We also show that different types ofcontact binaries have well defined locations on the mass ratio -luminosity ratio diagram. Several contact binary systems do not followLucy's relation (L2/L1 =(M2/M1)0.92). No strict mass ratio -luminosity ratio relation of contact binary stars exists.Tables 2 and 3 are available in electronic form athttp://www.edpsciences.org
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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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Times of Minima of Eclipsing Binary Systems DO Cas, V1143 Cyg, GO Cyg, and VW Cep
11 photoelectric minima are presented from the observations of 4eclipsing binaries.
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Short-Period Noncontact Close Binary Systems. VI. V392 Orionis
Photometric and spectroscopic observations in the optical region of theshort-period eclipsing binary system V392 Ori (A5 V, P=0.6593d) wereperformed and light and radial velocity curves were obtained. The lightcurves taken at various times are slightly different from one another.Analyses of the light and radial velocity curves yielded photometric andspectroscopic elements of the system. The derived mass function is quitesmall, f(M) = 0.0108 Msolar. The masses of the primary and secondarycomponents were found to be 1.2 Msolar and 0.3 Msolar, respectively, andthe radii are 1.7 Rsolar and 0.9 Rsolar. V392 Ori was found to belong toa group of low-mass binary systems. Due to the semidetached nature ofthe system, the loss of mass/angular momentum from the system mayoccasionally occur, inducing a probable effect on the light curves ofthe system. We compare the system with other low-mass binary systems anddiscuss the e volutionary status of the system.
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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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CN Andromedae: A Broken-Contact Binary?
We solve new UBV light curves of the eclipsing binary CN Andromedaesimultaneously with radial velocities by the method of differentialcorrections. We find it semidetached with the more massive star fillingits limiting lobe and the less massive star very close to lobe-filling.Our solutions of earlier light curves have the same configuration.Within the uncertainties, the system may be in a broken or a marginalcontact stage as it undergoes thermal relaxation oscillations. The lightcurves are strongly affected by a large dark spot at high latitude onthe more massive star and by a bright substellar spot on the companion.Spot locations and temperatures do not differ significantly from epochto epoch. Based on single star evolutionary models, the primary's mass(1.299+/-0.045 Msolar) and radius (1.425+/-0.016Rsolar) are consistent with those of a star of age2.9×109 yr that will leave the main sequence in another2.0×109 yr. The orbital period has decreased during thepast 50 yr according to traditional eclipse timings and also accordingto our generalized light and velocity solutions that include a referenceepoch T0 and a rate of period change dP/dt. We finddP/dt=-0.01951+/-0.00054 s yr-1, which is consistent withmass transfer from the more to the less massive star of1.4×10-7 Msolar yr-1, assuming nomass is lost from the system. Reliable absolute dimensions aredetermined.
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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
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Near-Contact Binary Systems in the ROSAT All-Sky Survey
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJ...461..951S&db_key=AST
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RS CVn Versus Algol-Type Binaries: A Comparative Study of Their X-Ray Emission
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....111.2415S&db_key=AST
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On the nature of the AM phenomenon or on a stabilization and the tidal mixing in binaries. I. Orbital periods and rotation.
The paper casts a questioning eye on the unique role of the diffusiveparticle transport mechanism in explaining the Am phenomenon and arguesthat the so-called tidal effects might be of great importance incontrolling diffusion processes. A short period cutoff at =~1.2d as wellas a 180-800d gap were found in the orbital period distribution (OPD) ofAm binaries. The existence of the former can be ascribed to the state ofthe primaries with the almost-filled Roche lobes. The latter couldresult from the combined effects of the diffusion, tidal mixing andstabilization processes. Because the tidal mixing might surpassdiffusion in the binaries with the orbital periods P_orb_ less thanseveral hundred days and might thus sustain the He convection zone,which would otherwise disappear, no Am stars should lie below thisboundary. The fact that they are nevertheless seen there implies theexistence of some stabilization mechanism (as, e.g., that recentlyproposed by Tassoul & Tassoul 1992) for the binaries with orbitalperiods less than 180d. Further evidence is given to the fact that theOPD for the Am and the normal binaries with an A4-F1 primary arecomplementary to each other, from which it stems that Am stars are closeto the main sequence. There are, however, indications that they haveslightly larger radii (2.1-3 Rsun_) than expected for theirspectral type. The generally accepted rotational velocity cutoff at=~100km/s is shown to be of little value when applied on Am binaries ashere it is not a single quantity but, in fact, a function of P_orb_whose shape is strikingly similar to that of the curves of constantmetallicity as ascertained from observations. This also leads to thewell known overlap in rotational velocities of the normal and Am starsfor 402.5d.We have exploited this empirical cutoff function to calibrate thecorresponding turbulent diffusion coefficient associated with tidalmixing, having found out that the computed form of the lines of constantturbulence fits qualitatively the empirical shape of the curves ofconstant metallicity. As for larger orbital periods(20d55km/s found by Burkhart(1979) would then be nothing but a manifestation of insufficientlypopulated corresponding area of larger P_orb_.
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Photoelectric Observations of the Eclipsing Variable DO Cas
Not Available
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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.
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Near-contact binaries
Not Available
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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.
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Search for contact systems among EB-type binaries. IV - V375 Cas, UW Ori, DO Cas, RU ERI
We present the analysis of the data of four EB-type eclipsing binaries,continuing our search for contact or almost contact systems. The Pricealgorithm has been used in conjunction to the Wilson-Devinney model totry to obtain, where possible, unambiguous solutions for all thesystems.
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The gravity-darkening of highly distorted stars in close binary systems. VIII - Practical analysis of primary components filling the critical Roche lobe in semi-detached systems of reverse Algol-type
The effective gravity-darkening is studied for the primary componentsfilling the critical Roche lobe in eight semi-detached systems ofreverse Algol-type. From the analysis of light variations outsideeclipses, values of the exponent of gravity-darkening for thesecomponents have been deduced with the assumed values for the secondarycomponents. The derived values of the exponent are found to be greaterthan the unity, confirming the previous result that the empirical valueof the exponent of gravity-darkening for a component star filling thecritical lobe is generally greater than the unity. It is also found thatthe values derived here for the primary components of the reverse Algolsare distinctly smaller than those derived for the secondary componentsin semi-detached systems of normal Algol-type. Based on the mass-outflowdarkening model, the present result would thus indicate that the ratesof mass transfer in reverse Algols are not so high, and might imply thatthe systems are not in the rapid phase of mass transfer
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Evolutionary state of W UMa-type systems
The evolutionary status of a sample of 31 W UMa-type systems isdiscussed on the basis of their positions in the H-R, mass-radius andmass-luminosity diagrams. The absolute elements of these systems areevaluated by use of their spectroscopic and photometric data. This givesthe opportunity to make different H-R, mass-radius, and mass-luminositydiagrams, according to the method used, and compare the results.Moreover, from the spectral type-period diagram of those systems thathave spectral types from O to G2 it was found that all of them lie inthe evolved region.
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EB-type contact binary DO CAS with a large temperature difference
New UBV photoelectric observations of EB-type contact binary DO Cas weremade on four nights from February 1986 to February 1987. The obtainedlight curves in combination with the radial-velocity curve of theprimary published by Mannino (1958) of DO Cas have been solvedsimultaneously using the Wilson-Devinney synthesis code. The system isfound to be a contact binary with a degree of overcontact of 14 percent.It may be concluded that DO Cas is an evolved contact binary.
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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.
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Search for contact systems among EB-type binaries. I - TT Herculis
In a search of contact systems among EB-type binaries, the existingphotometric observations of TT Her have been analyzed. An unambiguoussolution, contrary to previous analyses which presented severalpossibilities is found. The system is semi-detached, with the primaryfilling the lobe. There is evidence that the primary is evolved off themain sequence, and that mass transfer is taking place from the primaryto the secondary, which is therefore enlarged by accretion. Thetemperature of the primary component is found to be about 7240 K, thussolving one of the problems for this system. It is concluded that TT Heris the progenitor of an evolved contact binary.
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A note on thermally decoupled W Ursae Majoris systems
The thermal decoupling degree of short-period contact or near-contactsystems is studied. Statistics of well-observed W UMa systems includingnew beta-light-curve objects was made for thermal-decoupling degree,spectral type, and orbital period. W UMa systems of type A and W arefound to be well characterized by these parameters. W-type objects showa good (linear) correlation in the spectral type vs. thermal-decouplingparameter diagram. This extends to the lower border of the diagram forA-type systems, otherwise scattered in an area of large thermaldecoupling. These empirical facts are analyzed in terms of contact ornoncontact configurations.
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Photometric analysis of DO Cassiopeiae
Photoelectric observations of DO Cas in B and V were obtained during 7nights in 1984. The mass ratio was determined to be 0.397 using theWilson-Devinney method. It is shown that DO Cas is a semidetached systemwith the more massive primary component filling the Roche lobe.Mannino's (1958) spectroscopic results were combined with thephotometric results to determine absolute dimensions. It is found thatthe period of DO Cas alternates in sign with a period of about 25 years.
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Eclipsing Binaries - Cancer to Corona Borealis in 1972-1984
Not Available
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The system of DO Cassiopeiae - Photoelectric observations and light curves analysis
The new B and V photoelectric observations of DO Cas, obtained during1979 and 1980, are presented, analyzed, and discussed. The observationswere made at the National Observatory of Athens, Greece, and theiranalysis was based on the frequency domain, techniques. New geometric,photometric, and absolute elements for the system are given.
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Photoelectric Minima of Eclipsing Binaries
Not Available
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Synthetic light curve solutions for the short-period eclipsing binaries ST Aqr, DO Cas, and TX CET
Synthetic light curve solutions of the short-period binary systems STAqr, DO Cas, and TX Cet are presented. Their evolutionary state isbriefly discussed.
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Geometrical and physical elements of four Beta Lyrae type eclipsing variables
The aim of the present paper is to present an analysis of light changesof four Beta Lyrae eclipsing systems (DO Cas, KR Cyg, V388 Cyg, and SVCen) using automated Fourier techniques in the frequency-domain. Theapplicability of the above method to the Beta Lyrae system is discussed.New physical and geometrical elements of these systems are derived.Their positions in the H-R diagram and mass-luminosity diagram areindicated.
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INHABITED SKY
