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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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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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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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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Open clusters with Hipparcos. I. Mean astrometric parameters
New memberships, mean parallaxes and proper motions of all 9 openclusters closer than 300 pc (except the Hyades) and 9rich clusters between 300 and 500 pc have been computed using Hipparcosdata. Precisions, ranging from 0.2 to 0.5 mas for parallaxes and 0.1 to0.5 mas/yr for proper motions, are of great interest for calibratingphotometric parallaxes as well as for kinematical studies. Carefulinvestigations of possible biases have been performed and no evidence ofsignificant systematic errors on the mean cluster parallaxes has beenfound. The distances and proper motions of 32 more distant clusters,which may be used statistically, are also indicated. Based onobservations made with the ESA Hipparcos astrometry satellite
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An X-Ray Survey of the Open Cluster NGC 6475 (M7) With ROSAT
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....110.1229P&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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Physical characteristics of close binary system components
An approximate approach for evaluating the mass of invisible satellitesof close binary systems with the mass-function f(M) much less than 1 issuggested. A possibility of using it is shown for 62 close binarysystems.
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Giant CP stars?
This study is part of an investigation of the possibility of usingchemically peculiar (CP) stars to map local galactic structure. Correctluminosities of these stars are therefore crucial. CP stars aregenerally regarded as main-sequence or near-main-sequence objects.However, some CP stars have been classified as giants. A selection ofstars, classified in the literature as CP giants, are compared to normalstars in the same effective temperature interval and to ordinary'nongiant' CP stars. No clear confirmation of a higher luminosity for'CP giants' than for CP stars in general is found. In addition, CPcharacteristics seem to be individual properties not repeated in acomponent star or other cluster members.
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Experiments with CP stars
A method for fine-classification of stars is applied to a sample ofabout 100 stars within the approximate spectral type range B6-A5.Experiments have been performed to find a method for fine-classificationof A stars, both normal and chemically peculiar, within the MK system.It is found that, independent of the definition of the degree ofpeculiarity, no sharp border exists separating the CP stars from thenormal ones. It is also shown that spectral classification can, onaverage, be performed with almost the same accuracy for CP stars as forthe normal ones if cases of extreme peculiarity are avoided.
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The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotation
The MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars.
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Radial velocities and membership probabilities in the open star cluster NGC 6475 (M 7)
For 76 stars in the field of the open cluster NGC 6475, calibratedobjective prism radial velocities with a mean observational error near +or - 2 km/s are presented. HD 163302 has been detected to be a newspectroscopic binary. Preliminary orbital elements are given. Clusterand field stars are separated kinematically by their widely differentvelocity dispersions. A statistical interpretation of the velocitydistribution reveals quantitative membership probabilities. A largefraction of cluster members are still identified beyond the conventionalcluster radius. HD 162067 is discovered to be a high-velocity star witha radial velocity of nearly 100 km/s of approach.
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Observed and computed spectral flux distribution of non-supergiant O9-G8 stars. III - Determination of T(eff) for the stars in the Breger Catalogue
The effective temperatures and angular diameters of nonsupergiant O9-G8stars are determined from visible spectrophotometry. The results, whichrefer to 302 stars included in the Breger Catalogue, are derived fromthe comparison between the observed flux distributions and thepredictions of Kurucz's models (1979). The uncertainties to be expectedin individual results are discussed; their sizes are of the order of 5percent in effective temperature and 10 percent in angular diameter.
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The period distribution of unevolved close binary systems
Period distributions have been examined for various spectral types ofabout 600 (eclipsing and spectroscopic) close binaries, which are likelyto be substantially unevolved. The comparison with the previouscorresponding analyses of extensive (but heterogeneous) binary samplesallows a clarification of the extent of the evolutionary andobservational selection effects. Remarkably, this analysis reveals agreat deficiency of short period binaries (with periods corresponding tocase A mass transfer) in the whole spectral range. For the late spectraltypes, this result may be connected with postformation angular momentumloss caused by stellar wind magnetic braking; at least for the late Band A spectral range, a ready interpretation of this finding is thatclose binaries of corresponding periods and spectral types are rarelyformed.
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Catalogue of Eclipsing and Spectroscopic Binary Stars in the Regions of Open Clusters
Not Available
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A study of the open cluster NGC 6475 (M 7) (and two other stellar clusterings)
The open cluster NGC 6475 has been investigated with respect to possiblephysical properties common for its members and hence useful fordiscrimination purposes. As comparison objects two loose clusterings ofA-type stars in the southern Milky Way were used. The investigationincludes studies of both intermediate-dispersion spectra (20 A/mm) andUBV photometry. The general impression is that the high frequency ofmultiple stars, visual as well as spectroscopic, will constitute a veryserious obstacle as far as physical discrimination of cluster members isconcerned and to a large extent also in the case of other studies. TheCP stars appearing in NGC 6475 have also been subject to somediscussion. If continued investigations should prove multiplicity amongcluster stars to be considerably less frequent than in the presentcases, a membership criterion might be fruitful. Otherwise it probablyhas to be abandoned.
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A search for periodic variability of normal A-type stars
Detailed UBV measurements are presented for seventeen A-type stars, notclassified as peculiar, together with two peculiar A-type stars forcomparison. The results indicate that measurable variation is a rathercommon phenomenon among A-type stars.
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The open cluster NGC 3532
NGC 3532 is a large cluster in the Carina region of the southern MilkyWay. Observations in the modified Stromgren and H beta systems have beenobtained for 33 stars. (R,I) photometry for the red stars is listed in atable. The HD and CPD numbers for the 33 stars are also listed togetherwith the numbers assigned by Koelbloed. Attention is given to reddeningand luminosity determinations, the red giants in the cluster region, acomparison of computed and cluster luminosities for some of thecalibrating stars, and age considerations. It is pointed out that theusefulness of NGC 2287 and 3532 for testing stellar models is increasedby the existence of a third, bright cluster of intermediate age, NGC6475.
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Apparent radii and other parameters for 416 B5 V-F5 V stars of the catalogue of the Geneva Observatory
Apparent radius, visual brightness, effective temperature and absoluteradius for 416 B5 v-F5 v stars of the catalogue of the GenevaObservatory (Rufener, 1976) have been determined. Twenty-eight stars,anomalous in log a" versus (m~)o diagrams, have been singled out. A goodcorrelation for seven stars, in common with the list of Hanbury Brown etal. (1974), has been found. Similar parameters determined for 279 B5v-F5 v stars of two preceding papers (Fracassini et al., 1973, 1975)have allowed us to determine the averaged diagrams , and versus (B -V)0 for 695 B5 v-F5 v stars. Moreover, in the present paper a goodcorrelation versus and carefulrelation = -7.40 + 3.31 for B5v-F5 V stars have been determined. Plain correlations between log R/R0and blanketing parameter m2 for some spectral types seem to point outthat there are real differences in the absolute radii of stars of thesame spectral type, in agreement with recent researches on the HRdiagram (Houck and Fesen, 1978). Systematic differences between double(spectroscopic and visual) and single stars are found. In particular,the averaged relation versus shows that A2v-F5 v double stars may have a higher metallicity index m2 and smallerabsolute radii than single stars. Finally, the diagram log v sin iversus log R/R0 confirms some properties of binary systems found byother researchers (Huang, 1966; Plavec, 1970; Levato, 1974; Kitamura andKondo, 1978)
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Relative radial velocities from objective prism spectra in the region of nine southern open star clusters and a star field at Eta Carinae
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...41..245G&db_key=AST
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Seventh catalogue of the orbital elements of spectroscopic binary systems.
Not Available
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Errata in the "Bibliography of Stellar Radial Velocities" by H. A. Abt & E. S. Biggs
Not Available
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The spectroscopic binaries in NGC 6475
Using objective-prism spectra obtained with a radial-velocityastrograph, a large number of radial velocities of 13 of the brightestmembers in NGC 6475 have been determined. Three of five previouslysuspected short-period spectroscopic binaries could not be confirmed.However, two of these three stars seem to be long-period spectroscopicbinaries. The remaining two suspected binaries could be confirmed, andelements have been derived. It is concluded that the frequency ofshort-period spectroscopic binaries in NGC 6475 is considerably smallerthan supposed earlier. Finally, general properties of the techniqueemployed for the determination of relative radial velocities arediscussed.
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Nomenclature cross-correlation for stars in NGC 2516 and NGC 6475
Not Available
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Catalog of spectrophotometric scans of stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJS...32....7B&db_key=AST
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A photometric method for selecting AP stars
The paper describes a photometric method which is independent ofluminosity and interstellar reddening, developed for the selection of Apstars with spectral type earlier than A5, excluding Hg stars. Thismethod was applied to the star clusters measured by the photometricsystem of Geneva Observatory.
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Spectral types in the open cluster NGC 6475.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975PASP...87..417A&db_key=AST
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Rotational velocities and spectral types for a sample of binary systems.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&AS...19...91L&db_key=AST
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The Evolutionary Status of the Blue Halo Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973ApJS...26...37N&db_key=AST
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Spectroscopic binaries - 12th complementary catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...10..105P&db_key=AST
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INHABITED SKY
