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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
| On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Liste des étoiles Ap et Am dans les amas ouverts (édition révisée)
Not Available
| 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.
| Liste des étoiles Ap et Am dans les amas ouverts (Edition révisée)
Not Available
| 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.
| 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.
| 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.
| A spectrophotometric survey of stars along the Milky Way. IV
In the present paper a catalogue of spectrophotometric quantities,spectral types, monochromatic magnitudes and colour equivalents is givenfor all stars brighter than the magnitude m4400 = 10.5 in aregion of the Milky Way in Perseus. No absorption is found for starscloser than about r = 100 pc. The absorbing clouds are situated atdistances closer than 1 kpc and at about 2.5 kpc in the local arm andthe Perseus arm, respectively. The space between the two arms is freefrom absorption. It is also concluded that the Perseus arm continuesbeyond l = 140 deg, containing not only hydrogen gas but also dust to atleast l = 150 deg), while the content of OB stars decreases abruptly atl = 140 deg.
| 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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| קבוצת-כוכבים: | פרסאוס |
| התרוממות ימנית: | 04h14m57.15s |
| סירוב: | +51°13'56.2" |
| גודל גלוי: | 8.798 |
| מרחק: | 306.748 פארסק |
| תנועה נכונה: | 2.3 |
| תנועה נכונה: | -4.6 |
| B-T magnitude: | 9.03 |
| V-T magnitude: | 8.818 |
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