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|New catalogue of blue stragglers in open clusters|
We present a catalogue of blue-straggler candidates in galactic openclusters. It is based on the inspection of the colour-magnitude diagramsof the clusters, and it updates and supersedesthe first version(Ahumada & Lapasset 1995). A new bibliographical search was made foreach cluster, and the resulting information is organised into twotables. Some methodological aspects have been revised, in particularthose concerning the delimitation of the area in the diagrams where thestragglers are selected.A total of 1887 blue-straggler candidates have been found in 427 openclusters of all ages, doubling the original number. The catalogued starsare classified into two categories mainly according to membershipinformation.The whole catalogue (Tables 8, 9, notes, and references) is onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (126.96.36.199) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/463/789
|Metallicity distribution on the galactic disk|
Depending mainly on UBVCCD data, the metallicities of 91 open starclusters nearby the galactic disk have been estimated using Cameron's[A&A 147 (1985b) 39] method. The metallicity radial gradient alongthe galactic plane is found to be -0.09 dex/kpc; which is in a very goodagreement with Panagia and Tosi [A&A 96 (1981) 306] and Carraro etal. [MNRAS 296 (1998) 1045]. Vertically on the galactic disk, withinabout 800 pc, the metallicity gradient is found to be so trivial. Anaverage age-metallicity relation has been examined, which confirms theprevious suggestion that the metallicity of a cluster depending mainlyon its position on the galactic disk more than its age.
|Proper Motions of Open Star Clusters and the Rotation Rate of the Galaxy|
The mean proper motions of 167 Galactic open clusters withradial-velocity measurements are computed from the data of the Tycho-2catalog using kinematic and photometric cluster membership criteria. Theresulting catalog is compared to the results of other studies. The newproper motions are used to infer the Galactic rotation rate at the solarcircle, which is found to be ω0=+24.6±0.8 km s-1 kpc-1.Analysis of the dependence of the dispersion of ω0 estimates onheliocentric velocity showed that even the proper motions of clusterswith distances r>3 kpc contain enough useful information to be usedin kinematic studies demonstrating that the determination of propermotions is quite justified even for very distant clusters.
|Morphological analysis of open clusters' propertiesII. Relationships projected onto the galactic plane|
A morphological analysis study of open clusters' properties has beenachieved for a sample of 160 UBVCCD open star clusters of approximately128,000 stars near the galactic plane. The data was obtained and reducedfrom using the same reduction procedures, which makes this catalogue thelargest homogeneous source of open clusters' parameters.
|Morphological analysis of open clusters' propertiesI. Properties' estimations|
A sample of 160 UBVCCD observations of open star clusters near thegalactic plane has been studied, and a catalogue of their propertiesobtained. The main photometrical properties have been re-estimated selfconsistently and the results have been compared with those of Lynga[Lynga, G., 1987. Catalog of Open Cluster Data, 5th Edition, StellarData Centers, Observatoire de Strasbourg, France].
|A report on the studies of star clusters with the UPSO 104-cm Sampurnanand telescope during last 25 years|
|Hickson 96: a physical compact group.|
We analyze the morphology and dynamics of the galaxies of the Hickson 96compact group by means of deep CCD images in the B, V and R photometricbands and long-slit spectroscopy. The four galaxies of this spiral richgroup show signs of gravitational interaction. Two long tails come outfrom the contact region of the close pair H96ac. It is also there whereboth galaxies, bi-symmetrical in their inner parts, loose one of theirarms. Moreover, both the photometric and kinematical center of H96a aredisplaced relative to the center of the disk. H96b, a giant ellipticalgalaxy, shows significant deviations from a r^1/4^ law at the innerparts and small rotation along its major axis. We find at the centre ofthe galaxy an elongated component which is kinematically decoupled. Awide faint plume seems to emerge from this galaxy. H96d, the smallestgalaxy of the group, seems to be influenced by the bigger members, asindicated by three prominent knots of recent bursts of star formation inits blue disk, and by hints of optical bridges joining H96d with H96aand b. Finally the group has a low velocity dispersion (160km/s) and iswell isolated - no galaxies with comparable magnitude to H96a or H96bare found in its neighborhood. All these results lead us to concludethat Hickson 96 constitutes a real physical system.
|Spectroscopic observations of the young open cluster NGC 366.|
In this note we give the spectral classification for ten of thebrightest stars in the field of the young open cluster NGC 366. Thisallows us to obtain a reliable estimate of the individual reddenings,the distance and age of the cluster. One of the stars shows an emissionline spectrum, and is classified as Be. We confirm NGC 366 to be a veryyoung cluster (age ~10^7^yr) and we obtain a slightly smaller distancecompared to that given by Phelps & Janes (1994).
|CCD photometry of galactic open star clusters IV. NGC 366|
|Young open clusters as probes of the star formation process. 1: an atlas of open cluster photometry|
We have obtained charge coupled device (CCD) photometry, in the UBVsystem, for 23 open clusters in order to explore the star formationhistory of the Cassiopeia region of the Perseus spiral arm of ourGalaxy. Magnitudes and colors of 35,788 stars were measured, making thisthe most comprehensive, homogeneous single study of open clusterproperties in one part of the Galaxy. This paper presents an atlas ofopen cluster photometry that serves as the database for an investigationof cluster properties such as their ages, distances, reddenings, sizes,and richnesses. This information provides insight into the spatial andtemporal formation sequence of the clusters and allows an investigationof the stellar content of the clusters to be undertaken.
|Catalog of open clusters and associated interstellar matter.|
|A photographic survey of galactic clusters. V. NGC 189, I 1590, NGC 358, 366, 381, 433, 436, 457, 609, 637, I 166, NGC 743|
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