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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
| Radial Velocities, Binarity, and Kinematic Membership in the Open Cluster NGC 2516
We present echelle spectroscopic observations for 36 bright (V<9.6)stars in the open cluster NGC 2516, including several blue stragglercandidates and four red giants. Radial velocities are derived bycross-correlations using high signal-to-noise ratio standard spectra astemplates. From 22 cluster members a mean cluster velocity of+22.0+/-0.2 km s-1 was derived. Membership probabilities ofthe observed stars are computed on the basis of their distance to thecluster center and kinematic criteria. We report the discovery of threedouble-lined spectroscopic binaries and several probable binaries amongmain-sequence stars. A binary frequency of more than 26% is found amongthe high-mass main-sequence stars. The blue straggler HD 66341 is aslowly rotating cluster member with constant velocity, while HD 66194 isa fast-rotating Be star with probable variations in radial velocity.Other blue straggler candidates, such as HD 65663, 65950, 66066, and65987, must be considered turnoff stars. The observations presented herewere obtained at the Complejo Astronómico El Leoncito (CASLEO),which is operated under agreement between the Consejo Nacional deInvestigaciones Científicas y Técnicas de laRepública Argentina (CONICET) and the national universities of LaPlata, Córdoba, and San Juan.
| 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
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
| UBV photometry and the structure of the galactic cluster NGC 2516
UBV photoelectric magnitudes and colors for 106 stars, along withphotographic magnitudes and colors for 486 stars, in the vicinity of NGC2516 are presented. A true distance modulus of 8.18 + or - 0.38 mag isobtained which corresponds to a linear distance of 430 (-70,+80) pc.Evolutionary ages for the sample are found to average about 1.1 x 10 tothe 8th yr, while some of the brightest stars are much younger. Possibleexplanations for these different age groups are proposed.
| 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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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | שדרית |
| התרוממות ימנית: | 07h53m29.24s |
| סירוב: | -61°03'16.1" |
| גודל גלוי: | 7.814 |
| מרחק: | 458.716 פארסק |
| תנועה נכונה: | -4.9 |
| תנועה נכונה: | 10.5 |
| B-T magnitude: | 7.849 |
| V-T magnitude: | 7.817 |
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