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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Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
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The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars
The HR-diagram of about 1000 Bp - Ap stars in the solar neighbourhoodhas been constructed using astrometric data from Hipparcos satellite aswell as photometric and radial velocity data. The LM method\cite{luri95,luri96} allows the use of proper motion and radial velocitydata in addition to the trigonometric parallaxes to obtain luminositycalibrations and improved distances estimates. Six types of Bp - Apstars have been examined: He-rich, He-weak, HgMn, Si, Si+ and SrCrEu.Most Bp - Ap stars lie on the main sequence occupying the whole width ofit (about 2 mag), just like normal stars in the same range of spectraltypes. Their kinematic behaviour is typical of thin disk stars youngerthan about 1 Gyr. A few stars found to be high above the galactic planeor to have a high velocity are briefly discussed. Based on data from theESA Hipparcos astrometry satellite and photometric data collected in theGeneva system at ESO, La Silla (Chile) and at Jungfraujoch andGornergrat Observatories (Switzerland). Tables 3 and 4 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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Catalogue of blue stragglers in open clusters.
An extensive survey of blue straggler candidates in galactic openclusters of both hemispheres is presented. The blue stragglers wereselected considering their positions in the cluster colour-magnitudediagrams.They were categorized according to the accuracy of thephotometric measurements and membership probabilities. An amount of 959blue straggler candidates in 390 open clusters of all ages wereidentified and classified. A set of basic data is given for everycluster and blue straggler. The information is arranged in the form of acatalogue. Blue stragglers are found in clusters of all ages. Thepercentage of clusters with blue stragglers generally grows with age andrichness of the clusters. The mean ratio of the number of bluestragglers to the number of cluster main sequence stars is approximatelyconstant up to a cluster age of about 10^8.6^ yr and rises for olderclusters. In general, the blue stragglers show a remarkable degree ofcentral concentration.
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A new list of effective temperatures of chemically peculiar stars. II.
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Liste des étoiles Ap et Am dans les amas ouverts (édition révisée)
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The formation of Be stars through close binary evolution
The possibility that Be stars are the remnants of case B mass transferin intermediate-mass close binaries is investigated. It is shown thatonly progenitors with mass ratios greater than a certain minimum valueq-min are capable of producing a Be star after the mass transfer. Thevalue of q-min lies between 0.3 and 0.5, depending on the evolutionparameters as well as on the observationally determined lower mass limitof Be/X-ray binaries. In more than 80 percent of the predicted systems,the evolved companion is an He star, particularly among the late-type Bstars; these systems may be detectable as XUV sources.
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Liste des étoiles Ap et Am dans les amas ouverts (Edition révisée)
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Catalog of AP and AM stars in open clusters
The previous results of Raab (1922), Markarian (1951), and Collinder(1931) have been used to catalog Ap and Am stars that are in the fieldof open clusters. Tabular data are presented for the clusterdesignation, the HD or HDE number, the right ascension (1900), thedeclination (1900), and the magnitude. Also listed are the spectraltypes and, for certain stars, the probability of cluster membership.
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Chemically peculiar stars in open clusters. I - The catalog
The largest existing compilation is presented of Ap and Am open clusterstars. The catalog contains information on 381 chemically peculiar (CP)stars of the upper main sequence in 79 open clusters. The catalog iscomposed of the following tables: (1) the main body, which lists CP (orsuspected CP) stars which are kinematical (or suspected kinematical)members of open clusters; (2) the list of CP (or suspected CP) starssometimes numbered among cluster members but which are actuallykinematical nonmembers; (3) the list of stars sometimes designated as'peculiar' but, in fact, probably not CP; (4) references for numberingsystems of cluster stars; (5) references for membership; and (6)references for spectral and/or peculiarity types.
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Intermediate and narrow band photometry of newly discovered CP 2 stars
From Bidelman's list (1983) of northern stars of astrophysical interesteleven chemically peculiar early type (CP2) stars were photometricallyinvestigated to check the reported CP2 character by means of the Delta-aphotometry and to obtain Stroemgren and H-beta values. The CP2 characterof all stars is verified, in one case the star belongs to a hottersubgroup than reported. One star (BD + 24 deg 3675) turns out to bevariable and shows the largest Delta-a value ever measured. Besidesthis, two stars from the Bright Star Catalogue were found to be CP2stars.
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Statistical Investigation of Chemically Peculiar Stars - Part Four - Luminosity of Different Type Stars
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The spectra and ages of blue stragglers
A mechanism similar to Wheeler's 'quasi-homogeneous evolution' and Finziand Wolf's proposal for blue stragglers is proposed as the origin of theblue stragglers in intermediate-age clusters. Blue stragglers are starswhose positions in color-magnitude diagrams of open and globularclusters are significantly above the turn-off points and in the regionof the (former) main sequence; they seem to represent a conflict withthe general conclusion that all stars in a cluster originated at aboutthe same time. It is concluded that there are at least two kinds of bluestragglers: (1) those stars of types about B3-A2 are primarily Ap starsand slow rotators, occur in the intermediate age clusters and remain inthe main sequence region probably through magnetic mixing; and (2) thestars of type O6-B2 frequently have emission lines, are rapid rotators,occur in the young cluster, and remain in the main sequence regionprobably by rotational mixing.
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Peculiar stars in the association Per OB2.
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Objective-prism discoveries in the northern sky. I
Attention is given to 175 northern hemisphere stars whose newlyrecognized peculiar, or otherwise prepossessing characteristics havebeen noted in a preliminary inspection of moderate dispersion objectiveprism plates. The plates were obtained with a 10-deg prism. The starlist gives HD or BD, alpha and delta values, magnitude, and type.
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Stellar content of young open clusters. I - Blue stragglers. II - Be stars
The properties of the blue stragglers and Be stars found in openclusters younger than the Hyades are examined. Thirty-nine bluestragglers were detected at the left of the upper main sequence in thecolor-magnitude diagrams of 75 open clusters, with the frequency ofdetection noted to increase with cluster age. About half of thestragglers show peculiar abundance characteristics corresponding tospectral classes Am, Ap, Bp, Be and Of. The spectroscopic andphotometric behavior of the blue stragglers is, however, identical withthat of main sequence stars of the same type and peculiarity. It issuggested that the blue stragglers with peculiar spectroscopiccharacteristics may result from the evolution, perhapsquasi-homogeneous, of abnormal stars. Analysis of the absolutemagnitudes and dereddened colors calculated for 94 Be stars in 34 openclusters indicates the distribution to peak at spectral types B1-B2 andB7-B8, and in clusters with turn-up types at B1-B2. Cluster Be starsoccupy the whole main sequence band, and evolutionary states from nearlyunevolved to fully evolved. They may be classified according to theirposition on the color-magnitude diagram, with the distinctions betweenclasses also related to spectroscopic differences.
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Spectroscopic studies of stars in Per OB2.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977AJ.....82..598G&db_key=AST
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Catalogue of early-type stars measured in a narrow-band photometric system
A compilation of the photoelectric measurements in the Barbier-Morguleffsystem is presented. The catalogue includes data for 773 stars ofspectral type 08 to F6. 706 stars have been measured at least twice.
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Distance Moduli of Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965ApJS...12..215H&db_key=AST
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Catalogue et bibliographie des étoiles A à spectre particulier - Deuxième supplément
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Spectral Classification in Some Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...134..612S&db_key=AST
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A Study of the II Persei Association.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960ApJ...132...58S&db_key=AST
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INHABITED SKY
