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Photometric and Coravel observations of red giant candidates in three open clusters: membership, binarity, reddening and metallicity
Aims.We present new CORAVEL radial-velocity observations andphotoelectric photometry in the UBV and DDO systems for a sample ofpotential members of the red-giant branches of NGC 6192, NGC 6208 andNGC 6268, three open clusters projected close to the Galactic centerdirection. We also examine the properties of a sample of 42 inner diskopen clusters projected towards almost the same direction as the threeclusters. Methods: .Cluster members and red field giants werediscriminated by using the CORAVEL radial-velocity data and by applyingtwo photometric criteria. Interstellar reddening and metal content ofthe clusters were derived from combined BV and DDO data. Results:.Cluster membership for five red giants in NGC 6192, three in NGC 6208and three in NGC 6268 has been confirmed by the analysis of thephotometric and kinematic data. Photometric membership probabilitiesshow very good agreement with those obtained from CORAVEL radialvelocities. Three new spectroscopic binaries were discovered among thered giants of NGC 6192 and NGC 6208. Mean radial velocities and E(B-V)colour excesses were derived. Conclusions: .The overallmetallicities were found to be nearly solar for NGC 6208 and above solarfor NGC 6192 and NGC 6268. Most of the clusters located closer than 2kpc from the Sun in the considered direction are slightly more reddenedthan the absorption resulting from the Baade's window absorption law.
| Proper motion determination of open clusters based on the UCAC2 catalogue
We present the kinematics of hundreds of open clusters, based on theUCAC2 Catalogue positions and proper motions. Membership probabilitieswere obtained for the stars in the cluster fields by applying astatistical method uses stellar proper motions. All open clusters withknown distance were investigated, and for 75 clusters this is the firstdetermination of the mean proper motion. The results, including the DSSimages of the cluster's fields with the kinematic members marked, areincorporated in the Open Clusters Catalogue supported on line by ourgroup.
| A deep Hα survey of the Milky Way. VI. The l = 332° area
The Galactic plane has been observed between l= 330° to l= 336°as part of a velocity resolved Hα survey of the southern Milky Wayusing a scaning Fabry-Perot on a 36 cm telescope. The detailed analysisof the resultant Hα profiles reveals the presence of severallayers of ionized gas with different velocities over the surveyedregion. We have studied in detail both the 2-D spatial and velocitystructure of the HII regions RCW102, RCW104 and RCW106. Combining theseHα observations with stellar and radio data we provide estimatesfor the most probable distances of these different layers. The firstlayer at -5 km s-1 is local emission linked to the Sco-Cenassociation at 170 pc. The next layer, around -24 km s-1, isat 1.9 kpc and traces the near section of the Sagittarius-Carina arm.Well connected to the Sagittarius-Carina arm portions traced in theadjacent regions (l= 328° and l= 338° area), the arm, in thislongitude range, clearly shows and confirms the departure from alogarithmic spiral. The Scutum-Crux arm is also traced in this area byfaint and diffuse emission at -40 km s-1 which can be placedat 3.2 kpc. The layer at -52 km s-1 is the major spiral-armfeature of the studied area; its most probable stellar distance is 4.2kpc. An important emission component is also observed at -65 kms-1 in the southern part of the surveyed area. This mainlypatchy and filamentary emission we identify as the possible opticalcounterpart of a supernovae remnant centered at l= 332.0°,b=-3.2°. Finally, two complexes have been determined around 12.5 kpcwhich places them in the far section of the Norma arm.Based on observations collected at the European Southern Observatory.Table \ref{tab1} is only available in electronic form athttp://www.edpsciences.org
| Deepsky delights.
Not Available
| New catalogue of optically visible open clusters and candidates
We have compiled a new catalogue of open clusters in the Galaxy whichupdates the previous catalogues of Lyngå (\cite{Lynga1987}) and ofMermilliod (\cite{Mermilliod1995}) (included in the WEBDA database). Newobjects and new data, in particular, data on kinematics (proper motions)that were not present in the old catalogues, have been included.Virtually all the clusters (1537) presently known were included, whichrepresents an increment of about 347 objects relative to the Lyngå(\cite{Lynga1987}) catalogue. The catalogue is presented in a singletable containing all the important data, which makes it easy to use. Thecatalogue can be accessed on line either athttp://www.astro.iag.usp.br/~wilton/ or as an electronic table whichwill be made available at the CDS. Tables 1a, 1b, 2 and 3 are onlyavailable in electronic form at http://www.astro.iag.usp.br/wilton/, orat the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/389/871
| Two highly reddened young open clusters located beyond the Sagittarius arm
We present the results of CCD BVI Johnson-Cousins photometry down to V ~19 mag in the regions of the unstudied stellar groups Pismis 23 and BH222, both projected close to the direction towards the Galactic centre.We measured V magnitude and B-V and V-I colours for a total of 928 starsin fields of about 4arcmin x4arcmin . Pismis 23 is conclusively aphysical system, since a clear main sequence and other meaningfulfeatures can be seen in the colour-magnitude diagrams. The reality ofthis cluster is also supported by star counts carried out within andoutside the cluster field. For Pismis 23 we derive colour excessesE(B-V) = 2.0 +/- 0.1 and E(V-I) = 2.6 +/- 0.1, a distance from the Sunof 2.6 +/- 0.6 kpc (Z = -19 pc) and an age of 300 +/- 100 Myr (assumingsolar metal content). BH 222 appears to be a young open cluster formedby a vertical main sequence and by a conspicuous group of luminous,typically red supergiant stars. We derived for this cluster a colourexcess of E(V-I) = 2.4 +/- 0.2, a distance from the Sun of 6.0 +/- 2.7kpc (Z = -46 pc) and an age of 60 +/- 30 Myr. The resulting reddeningand distance estimates place these two young objects among the mostreddened and distant open clusters known in the direction towards theGalactic centre. They are located beyond the Sagittarius arm, close tothe direction where this arm probably bifurcates into two arms. Based onobservations made at the University of Toronto (David DunlapObservatory) 24-inch telescope, Las Campanas, Chile. Tables \ref{t2} and3 are only available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/388/179
| Young stellar-gas complexes in the Galaxy
It is found that about 90 percent of OB-associations and o-b2 clusterssituated within 3 kpc of the sun can be united into complexes withdiameters of 150-700 pc. Almost all of these clusters contain giantmolecular clouds with a mass greater than about 100,000 solar masses. Anumber of complexes are associated with giant H I clouds; a few of thesmall complexes are situated in the HI caverns. The concentration ofOB-associations and young clusters in star complexes attests to theircommon origin in the supergiant gaseous clouds.
| Open clusters and galactic structure
A total of 610 references to 434 clusters are employed in thecompilation of a catalog of open clusters with color-magnitude diagramson the UBV or RGU systems. Estimates of reddening, distance modulus, ageand number of cluster members are included. Although the sample isconsidered representative of the discoverable clusters in the galaxy,the observed distribution is nonuniform because of interstellarobscuration. Cluster distribution in the galactic plane is found to bedominated by the locations of dust clouds rather than by spiralstructure. The distributions of clusters as a function of age andrichness class show that the lifetimes of poor clusters are much shorterthan rich ones, and that clusters in the outer disk survive longer thanthose in the inner disk. An outer disk age which is only about 50% theage of the globular clusters is indicated by cluster statistics. Thethickening of the galactic disk with increasing galactocentric distancemay be due to either a younger dynamical age or a lower gravitationalpotential in the outer regions.
| A catalogue of galactic clusters observed in three colours
This catalogue contains photometric data for 190 galactic clusters, allobserved in UBV or RGU. The distances of the young clusters (with spless than b3) have been calculated or recalculated according to method Aof Becker (1963). The galactic distribution of these clusters confirmstheir role of being good spiral tracers.
| Southern open stars clusters. III. UBV-Hbeta photometry of 28 clusters between galactic longitudes 297d and 353d
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...10..135M&db_key=AST
| Classification of open star clusters
Not Available
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