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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The Power of Archival Astronomy
Examples are given of the extreme usefulness of the Harvard CollegeObservatory Photographic Plate Collection for the study of variablestars that possess only limited published observational data. Programobjects studied with the aid of archival photographic data include: (i)the eclipsing binary HD 174403, (ii) the semiregular variable BC Cygni,(iii) V439 Cygni, now recognized as a gamma Cassiopeiae variable, and(iv) the classical Cepheid T Antliae. In the Case of T Antliae, theplate archives yielded not only data for the star's brightnessvariations but also for the spectral characteristics of all starsbrighter than B = 12 in the field.
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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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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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Empirical temperature calibrations for early-type stars
Three temperature calibrations of suitable photometric quantities havebeen derived for O and B stars. A sample of 120 stars with reliableT(eff.) determinations has been used for establishing each calibration.The different calibrations have been critically discussed and compared.Temperature determinations for 1009 program stars have been obtainedwith an accuracy of the order of 10 percent.
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Light variations of massive stars (Alpha Cygni variables). IX
High-precision VBLUW photometry of 22 highly luminous OBA-type stars, 13of which are Alpha Cygni variables and two of which are variable only incolor, is presented. It is suggested that sigma (V-B) increases fasterthan sigma (B-L) with later spectral types due to the absence ofstochastic metal line strength variations in the V band. It is assumedthat short-time-scale stellar spot activity is present, or thattemperature and density waves move through the atmospheres with the sametime scales, producing these line strength variations independent of thecontinuum variations. The possibility of differentiating stars which lieclose to each other in the HR diagram but have different evolutionaryhistories (and thus different metal abundances) with the aid of themaximum light amplitude/sigma (V-B) diagram is considered.
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Spectroscopic binaries - 15th complementary catalog
Published observational data on the orbital characteristics of 436spectroscopic binaries, covering the period 1982-1986, are compiled intables. The data sources and the organization of the catalog are brieflydiscussed, and notes are provided for each item.
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E(B-V) determination from an UV-visual two-colour diagram - O and B stars in the Catalogue of Stellar Ultraviolet Fluxes
For the O and B type stars in the Catalogue of Stellar UltravioletFluxes, an approach is presented which does not require a preciseknowledge of spectral type and luminosity class for deriving E(B-V)color excesses. The method is based on the use of an UV-visual two-colordiagram; galactic variations in the interstellar extinction law areanalyzed and fully taken into account. The results have been comparedwith those derived by using the differences between observed andintrinsic colors for stars with known spectral classification. The verygood agreement in a large number of cases (94 percent) demonstrates thatthe present approach permits the derivation of reliable color excessvalues for early-type stars even if only a rough spectral classificationis available.
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Comparsion Stars which Turn Out to be Variable
Not Available
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A photometric investigation of cluster membership for the Cepheid BB Sagittarii
Photoelectric UBV and VRI photometry is presented for the close pair ofopen clusters Cr 394 and NGC 6716 and for the 6.64 d classical CepheidBB Sgr. For Cr 394, E(B-V) = 0.25 + or - 0.01, V(0)-M(V) = 9.04 + or -0.08, d = 643 + or - 25 pc, age is about 60 million yr, nuclear radiusis 9 arcmin, and tidal radius is 27 arcmin. For NGC 6716, E(B-V) = 0.11+ or 0.01, V(0)-M(V) = 9.07 + or - 0.17, d = 650 + or - 52 pc, age isabout 60 million yr, nuclear radius 7 arcmin. The data combined withstar counts for the region of the cluster demonstrate that the Cepheidis a likely member of Cr 394.
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The 67th Name-List of Variable Stars
Not Available
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A Preliminary Ephemeris for the Newly Discovered Eclipsing Binary HD 174403 (A Possible Companion to the Cepheid BB Sgr?)
Not Available
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Color excesses of classical cepheids. I
The color excesses of eleven cepheids have been determined with the aidof photometry of field stars found in the proximity of the variables. Acomparison of the color excesses with previous color-excess results isgiven. Four cepheids: RT Aur, DT Cyg, Zeta Gem, and T Vul, haverelatively small and well-established reddening values. These fourstars, along with Alpha UMi, can serve as standards to calibratereddening-free indices with intrinsic color indices such as (b-y) or(B-V).
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Five-channel photometry of cepheids and supergiants in the southern Milky Way.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...24..413P&db_key=AST
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A study of visual binaries having primaries above the main sequence.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960AJ.....65...60S&db_key=AST
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INHABITED SKY
