Mass-luminosity relation for massive stars
A catalog of massive (⩾10 M ȯ) stars in binary andmultiple systems with well-known masses and luminosities has beencompiled. The catalog is analyzed using a theoretical mass-luminosityrelation. This relation allows both normal main-sequence stars and starswith peculiarities: with clear manifestations of mass transfer, massaccretion, and axial rotation, to be identified. Least-squares fittingof the observational data in the range of stellar masses 10Mȯ ⩽ M ≲ 50 M ȯ yields therelation L ˜ M 2.76.
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Properties and nature of Be stars. 24. Better data and model for the Be+F binary V360 Lacertae
Aims.We include existing photometric and spectroscopic material with newobservations in a detailed study of the Be+F binary V360Lac. Methods: .We used the programs FOTEL and KOREL toderive an improved linear ephemeris and to disentangle the line profilesof both binary components and telluric lines. The BINSYN software suite(described in the paper) is used to calculate synthetic light curves andspectra to fit the {UBV} photometry, an {IUE} spectrum, blue and redground-based spectra, and observed radial-velocity curves.Results: .The observations provide evidence of circumstellar matter inthe system. The system model shows that the Be primary star iscritically rotating, and that the synchronously rotating secondary starfills its Roche lobe. The primary star has a mass of7.45ȯ. Radial-velocity observations establish a massratio of 0.163. Light curve synthesis demonstrates that the observedlight curves are controlled largely by tidal distortion and irradiationof the massive primary by the less massive secondary. Synthetic spectrafit both blue and red observed spectra with the exception of spectrallines affected by circumstellar matter in the system. The syntheticspectra allow for gravity darkening and are consistent with criticalrotation of the primary. Synthetic spectrum fits to a dereddened {IUE}spectrum produce a calculated system distance of 512 pc. This distanceis 2σ beyond the Hipparcos distance.
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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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Two- and Three-Dimensional Hydrodynamical Simulations of Mass Transfer in Semidetached Binaries with Explicit Radiative Cooling and Self-Absorption in Their Gaseous Envelopes
We have modeled the mass transfer in three Algol-type binaries usingtwo-and three-dimensional numerical hydrodynamical techniques. Radiativecooling and absorption in the envelopes surrounding the components ofthe close binaries are explicitly taken into account. The resultingenvelope temperatures are consistent with those observed. We derivedthese temperatures by considering the energy balance in the moving gas,including heating due to the numerical viscosity that is inherent to thesimulations and radiative cooling. The radiative cooling was calculatedassuming an optically thin plasma in a state of ionization balance.Taking into account both of these processes yielded temperatures of 400030 000 K in the disk around the accreting primary and in the commonenvelope surrounding the close binary. Our computations also indicatethat the envelope morphology is not sensitive to the radiative-coolingmodel used.
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Beobachtungssergebnisse Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V.
Not Available
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Close binary stars in ob-association regions i. preliminary investigation
We performed a sample of O- and B-eclipsing binary stars inOB-association regions and obtained the preliminary list of 147 binariesin 45 OB-association regions. We tried to elucidate the question whether(or not) the close binaries belong to corresponding OB-associations,from the commonness of their proper motions, radial velocities anddistances. Based on the completeness of the data,the binaries aredevided into three groups and the scheme for calculation of degree ofbelonging of stars to OB-associations is developed. Necessary data arenot available for nine systems and they are given in a specific table.For 12 cases, the binaries project onto the regions of two associations.We show that 33 (22.3%) close binary stars are members, 65 (43.9%) areprobable members and 39 (26.4%) are less probable members of theOB-associations. We find that 11 binaries belong to the Galaxybackground. The comparison of the distributions of orbital periods forthe binaries in OB-associations and for O-, B-binaries of the Galaxybackground shows their considerable differences in the vicinity of thetwo-day period.
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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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Two-Dimensional Hydrodynamical Modeling of Mass Transfer in Semidetached Binaries with Asynchronously Rotating Components
We have modeled the mass transfer in the three semidetached binaries UCep, RZ Sct, and V373 Cas taking into account radiative cooling bothimplicitly and explicitly. The systems have asynchronously rotatingcomponents and high mass-transfer rates of the order of 10-6 Mȯ/yr; they are undergoing various stages of their evolution. Anaccreting star rotates asynchronously if added angular momentum isredistributed over the entire star over a time that exceeds thesynchronization time. Calculations have indicated that, in the modelconsidered, mass transfer through the point L1 is unable todesynchronize the donor star. The formation of an accretion disk andouter envelope depends on the component-mass ratio of the binary. Ifthis ratio is of the order of unity, the flow makes a direct impact withthe atmosphere of the accreting star, resulting in the formation of asmall accretion disk and a relatively dense outer envelope. This is trueof the disks in U Cep and V373 Cas. When the component-mass ratiosubstantially exceeds unity (the case in RZ Sct), the flow forms alarge, dense accretion disk and less dense outer envelope. Taking intoaccount radiative cooling both implicitly and explicitly, we show that aseries of shocks forms in the envelopes of these systems.
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Drei langperiodische Bedeckungsveranderliche: RZ Scuti, RZ Ophiuchi und EE Cephei.
Not Available
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Envelope Ejection: An Alternative Evolutionary Process for Some Early Case B Binaries
We discuss the evolution of binaries with moderately high masses (~10-30Msolar) and with periods of ~3-300 days, corresponding mostlyto early case B. These are usually thought to evolve either byreasonably conservative Roche lobe overflow, if the initial mass ratiois fairly mild, or else by highly nonconservative common-envelopeevolution, with spiral-in to short periods (hours, typically), if theinitial mass ratio is rather extreme. We discuss here a handful ofbinaries from part of this period range (~50-250 days), which appear tohave followed a different path: we argue that they must have lost alarge proportion of initial mass (~70%-80%) but without shortening theirperiods at all. We suggest that their behavior may be due to the factthat stars of such masses, when evolved also to rather large radii, arenot far from the Humphreys-Davidson limit, where single stars lose theirenvelopes spontaneously in P Cygni winds, and so have envelopes that areonly lightly bound to the core. These envelopes therefore may berelatively easily dissipated by the perturbing effect of a companion. Inaddition, some or all of the stars considered here may have been closeto the Cepheid instability strip when they filled their Roche lobes. Oneor the other, or both, of high luminosity and Cepheid instability, incombination with an appropriately close binary companion, may beimplicated.
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Eclipsing Binary Stars: Past, Present, and Future
A brief history of eclipsing binary star light curve analysis and anoverview of the current state of affairs is given. The photometricsearches for extra-solar planets in the next few years will eventuallyresult in millions of light curves and such volumes of data will requirethe efforts of amateur astronomers in their analysis. This article is athinly veiled plea to AAVSO members to join the current efforts of a fewAAVSO members in the observation and analysis of eclipsing binary stars.
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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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Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veraenderliche Sterne e.V.
Not Available
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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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The use of the NextGen model atmospheres for cool giants in a light curve synthesis code
We have written a light curve synthesis code that makes direct use ofmodel atmosphere specific intensities, in particular the NextGen modelatmosphere grid for cool giants (Teff<= 6800 K and log(g)<= 3.5, Hauschildt et al. \cite{hauschildt99}). We point out thatthese models (computed using spherical geometry) predict a limbdarkening behaviour that deviates significantly from a simple linear ortwo-parameter law (there is less intensity at the limb of the star). Thepresence of a significantly nonlinear limb darkening law has two mainconsequences. First, the ellipsoidal light curve computed for a tidallydistorted giant using the NextGen intensities is in general differentfrom the light curve computed using the same geometry but with the blackbody approximation and a one- or two-parameter limb darkening law. Inmost cases the light curves computed with the NextGen intensities havedeeper minima than their black body counterparts. Thus the light curvesolutions for binaries with a giant component obtained with models withnear linear limb darkening (either black body or plane-parallel modelatmosphere intensities) are biased. Observations over a wide wavelengthrange (i.e. both the optical and infrared) are particularly useful indiscriminating between models with nearly linear limb darkening and theNextGen models. Second, we show that rotational broadening kernels forRoche lobe filling (or nearly filling) giants can be significantlydifferent from analytic kernels due to a combination of the nonsphericalshape of the star and the radical departure from a simple limb darkeninglaw. As a result, geometrical information inferred from Vrotsin i measurements of cool giants in binary systems are likewise biased.
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Is asynchronism in semidetached binary systems real?
We analyze statistical relationships between the parameters ofAlgol-type binaries with asynchronous rotation of the primary componentsand provide observational evidence for denser, more extended gaseousenvelopes in the eclipsing systems of this group. We conclude thatasynchronism of the primary components in such systems is not real. Thelines that are used to determine the rotational velocities of thesecomponents originate mostly in the part of the atmosphere which acquiresan additional angular momentum during the interaction with the gasstream and produces a transient accretion disk near the equatorialplane.
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Five-colour photometry of OB-stars in the Southern Hemisphere
Observations of OB-stars, made in 1959 and 1960 at the Leiden SouthernStation near Hartebeespoortdam, South Africa, with the VBLUW photometerattached to the 90 cm light-collector, are given in this paper. They arecompared with photometry obtained by \cite[Graham (1968),]{gra68}\cite[Walraven & Walraven (1977),]{wal77} \cite[Lub & Pel(1977)]{lub77} and \cite[Van Genderen et al. (1984).]{gen84} Formulaefor the transformation of the present observations to those of\cite[Walraven & Walraven (1977)]{wal77} and \cite[Lub & Pel(1977)]{lub77} are given. Table 4 is only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html
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Three-dimensional modeling of mass transfer in close binary systems with asynchronous rotation
We present the results of three-dimensional numerical simulations ofmass transfer in semi-detached binary systems in which the mass-losingstar is rotating. The cases of aligned and non-aligned asynchronousrotation of the donor star are considered; the resulting flow patternsare compared to the synchronous rotation case. The main properties ofthe flow, such as the formation of a circumbinary envelope, the absenceof a "hot spot" on the edge of the accretion disk, and the formation ofa shock wave along the flow edge, are qualitatively similar to thoseobtained earlier. For the case of nonaligned, asynchronous rotation, thebehavior of the disk and surrounding matter in an established flowregime reflects changes in the boundary conditions at the surface of thedonor star; in other words, a "driven disk" model is realized in thecalculations.
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Variations of the orbital periods in semi-detached binary stars with radiative outer layers
A detailed analysis of the period changes of sixteen semi-detachedbinaries which contain only stars with radiative outer layers(ET-systems) has been performed and their respective O-C diagrams arebrought and discussed. It was found that the course of the periodvariations is monotonic and in some systems the period is even constant.This detailed analysis of extensive sets of timings covering severaldecades brings a strong support to an earlier finding of te[Hall(1989)]{hal89} and develops it further. We show that all systems withthe orbital periods shorter than nine days display constant period orits increase, with the exception of an uncertain case of V 337 Aql. Thecourse of the period variations in TT Aur appears more complex but thecyclic term can be plausibly explained by the third body. A search forgeneral relations between the parameters of the systems and the periodchanges was undertaken. The mass ratio q appears to play a role in theperiod variations. Clear changes in systems with orbital periods shorterthan 9 days were detected only for q>0.4 while constant periods arecommon in systems with q<0.4 in this period range. The sense of thesecular changes in most systems is in accordance with the dominantconservative mass transfer in evolved binary and corresponds to the slowphase. The role of the evolutionary scenarios (case A versus B) and theinfluence of changes of the rotational angular momenta of the componentsare 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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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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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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Rotation of Algol binaries - a line profile model applied to observations.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996MNRAS.283..613M&db_key=AST
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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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DN Orionis: A Long-Period Mass-Transferring "Slightly Detached" Algol Binary
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....110.1809E&db_key=AST
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O I lamba 7774 absorption as a tracer of streams and disks in nondegenerate binary stars
We propose a new spectroscopic approach for observing circumstellarmatter in binary stars, based on the neutral oxygen lambda 7774absorption lines. We present oxygen equivalent widths and radialvelocities in 20 nondegenerate eclipsing binaries. We note limitationsand advantages of using this line to trace circumstellar matter inbinary systems, and confirm the presence of streams and rotatingaccretion disks in a number of short- long-period Algol systems. Wediscuss evidence for geometrically thick disks, and describe a smallradial infall superimposed on disk rotation in most long-period systems.We speculate that infall may be related to viscous dissipation in disks.We emphasize the great sensitivity of lambda 7774 in studying thekinematics of circumstellar matter in many nondegenerate binary stars.
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Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
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Flare activity in semi-detached binaries.
Not Available
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Binary-star light curve models
The historical development of binary-star light-curve models is tracedfrom the early 1900s to the present, with emphasis on recent progress. Amajor break with tradition occurred about 1970 when physical models,based on equipotentials and made possible by fast computers, replacedgeometrical models. Physical models have been improving in accuracy,efficiency, generality, and user friendliness. Further improvements canbe expected. Astrophysical advances due to the new models range from newways to estimate mass ratios and rotation rates to confirmation oftheoretical predictions about the structure of W Ursae Majoris stars andbehavior of irradiated convective envelopes. The morphology of closebinaries, including extensions to nonsynchronous rotation and orbitaleccentricity, is interwoven with physical models and their applications.The origins and influence of the four morphological types -- detached,semidetached, overcontact, and double contact -- are inseparable fromthe development of light-curve models. Parameter adjustment is an activearea, with contributions on Differential Corrections, the Marquardtalgorithm, the Simplex algorithm, and other methods for reaching aleast-squares minimum. Solutions with applied constraints andsimultaneous solutions of two or more kinds of observations are cominginto more frequent usage. Observables other than photometric brightnessinclude radial velocity, polarization, photospheric spectral lineprofiles, and spectral distributions due to circumstellar flows. Some ofthe newer models extend into these areas and are leading to new kinds ofobserving programs.
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RZ Scuti: New five-color observations, solutions, and photometric and spectroscopic rotations
We describe photometric solutions using new intermediate-band Iybvuobservations of RZ Scuti. Our solution gives a reliable value of therotation parameter F1 (phot) = 5.0, and verifies theconclusion of Wilson et al. that this binary is at or near thedouble-contact configuration. We comment briefly on differences betweenour solution and those of previous investigators. We obtain additionalspectra in an attempt to refine the rotational velocity of the hotprimary star, and use K1 and our photometric mass ratio toestimate F1 (spec). For this direct impactor, we estimatethat F1 (phot) approximately equals F1 (spec).
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INHABITED SKY
