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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 (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/463/789
| 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.
| The relatively young, metal-poor and distant open cluster NGC 2324
We have obtained CCD photometry in the Johnson V, Kron-Cousins I andCT1 Washington systems for NGC 2324, a rich open clusterlocated 35° from the Galactic anticentre direction. We measuredV magnitudes and V-I colours for 2865 stars and T1 magnitudesand C-T1 colours for 1815 stars in an area of 13.6 arcmin× 13.6 arcmin. The comparison of the cluster colour-magnitudediagrams with isochrones of the Geneva group yield E(V-I) = 0.33± 0.07 and V-MV = 13.70 ± 0.15 for log t = 8.65(t = 440 Myr) and Z = 0.008 ([Fe/H] = -0.40), and E(C-T1) =0.40 ± 0.10 and T1-MT1 = 13.65 ±0.15 for the same age and metallicity level. The resulting E(V-I)reddening value implies E(B-V) = 0.25 ± 0.05 and a distance fromthe Sun of (3.8 ± 0.5) kpc. Star counts carried out within andoutside the cluster region allowed us to estimate the cluster angularradius as 5.3 arcmin ± 0.3 arcmin (5.9 pc). When using the E(B-V)reddening value here derived and the original Washington photometricdata of \citet{gcm91} for the stars confirmed as red cluster giants fromCoravel radial velocities, we found [Fe/H] = -0.31 ± 0.04, whichis in good agreement with the best fits of isochrones. Therefore, NGC2324 is found to be a relatively young, metal-poor and distant opencluster located beyond the Perseus spiral arm. A comparison of NGC 2324with 10 well-known open clusters of nearly the same age shows that thecluster metal abundance and its position in the Galaxy are consistentwith the existence of a radial abundance gradient of -0.07 dexkpc-1 in the Galactic disc.
| Performance of the IIA mosaic CCD camera system
We evaluate performance of the 4K x 4K mosaic CCD camera systemdeveloped at the Indian Institute of Astrophysics using four ThomsonCCDs in a buttable configuration. The camera system consists of a mosaicCCD dewar developed to mount the four CCDs and an electronics controllerdesigned to control the mosaic configuration. A window based dataacquisition software is used to configure the controller and acquireimages from the camera. The calibration measurements indicate that all 4CCDs have similar characteristics with a gain of about 3.9 e/ADU, rmsnoise of ~ 19 e, full-well capacity of ~ 57 000 ADU, non-linearity of ~0.4% and peak quantum efficiency of ~ 40% in the red region. The problemof cross-talk is faced in this multi-readout system and a solution isoffered. The performance of the mosaic CCD camera has been foundsatisfactory at the telescope.
| A deep V I CCD photometric study of the neglected galactic star cluster NGC 6631
We present the V I CCD photometric observations of about 5500 stars upto a limiting magnitude of V ~ 20 in an area of ~ 16? x 16? around thecluster NGC 6631. The cluster parameters determined for the first timeby fitting the theoretical isochrones in the V, (V - I) diagram of thecluster stars are E (V - I) = 0.60 +/- 0.05 mag, distance = 2.6 +/- 0.5kpc, age = 400 +/- 100 Myr and metallicity, Z = 0.05. The clusterdiameter determined from the radial density profile is 4.8 +/- 0.5 pc.The mass function of the cluster has a slope of 2.1 +/- 0.5.
| Catalogue of Eclipsing and Spectroscopic Binary Stars in the Regions of Open Clusters
Not Available
| Variable stars in open clusters.
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