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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
| 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
| Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..104..101S&db_key=AST
| An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| 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.
| Four-color and H beta photometry for open cluster. II. NGC 6475.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976PASP...88..174S&db_key=AST
| Metal-rich globular clusters in the Galaxy. III - The 'X-ray' globular cluster NGC 6441. IV - A color-magnitude diagram for NGC 6304
Results are reported for UBV photoelectric and photographic observationsof about 700 stars in the southern globular cluster NGC 6441 and ofabout 385 stars in or near the G2 globular cluster NGC 6304. Features inthe color-magnitude diagrams of the clusters are found which indicatethat NGC 6441 is one of the most metal-rich clusters known in the Galaxyand that NGC 6304 is a moderately metal-rich cluster. No unusualfeatures in the color-magnitude diagram of NGC 6441 are detected thatmight account for its appearing in the error box of the X-ray source 3U1746-37, except possibly the anomalous position of the variable star V6in the diagram. Estimates are made of the foreground reddening, distancemoduli, and integrated absolute visual magnitudes of both clusters. Itis shown that NGC 6441 has a normal M/L ratio and is located atperigalacticon. NGC 6304 is shown to be located 450 pc above thegalactic plane and possibly to contain two RR Lyrae variables.
| Nomenclature cross-correlation for stars in NGC 2516 and NGC 6475
Not Available
| Observations of 3 novae in Sco.
Not Available
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Membro dei seguenti gruppi:
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Osservazione e dati astrometrici
| Costellazione: | Scorpione |
| Ascensione retta: | 17h51m02.13s |
| Declinazione: | -35°04'14.0" |
| Magnitudine apparente: | 7.599 |
| Distanza: | 336.7 parsec |
| Moto proprio RA: | 4.4 |
| Moto proprio Dec: | -5.3 |
| B-T magnitude: | 7.616 |
| V-T magnitude: | 7.601 |
Cataloghi e designazioni:
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