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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.
| On the distance, reddening and progenitor of V838 Mon
Extensive optical and infrared photometry as well as low and highresolution spectroscopy are used as inputs in deriving robust estimatesof the reddening, distance and nature of the progenitor of V838 Mon, the2002 outbursting event that produced a most spectacular light-echo. Thereddening affecting V838 Mon is found to obey the R_V=3.1 law andamounts to (i) EB-V=0.86 from the interstellar NaI and KIlines; (ii) EB-V=0.88 from the energy distribution of the B3V component; and (iii) EB-V=0.87 from the progression ofextinction along the line of sight. The adoptedEB-V=0.87±0.01 is also the amount required by fittingthe progenitor with theoretical isochrones of appropriate metallicity.The distance is estimated from (a) the galactic kinematics of the threecomponents of the interstellar lines; (b) the amount of extinction vs.the HI column density and vs. the dust emission through the whole Galaxyin that direction; from (c) spectrophotometric parallax to the B3 Vcompanion; from (d) comparison of the observed color-magnitude diagramof field stars with 3D stellar population models of the Galaxy; from (e)comparison of theoretical isochrones with the components of the binarysystem in quiescence and found to be around 10 kpc. Pre-outburst opticaland IR energy distributions show that the component erupting in 2002 wasbrighter and hotter than the B3 V companion. The best fit is obtainedfor a 50 000 K source, 0.5 mag brighter than the B3 V companion. Thelatter passed unaffected through the outburst, which implies an orbitalseparation wide enough to avoid mass exchange during the evolution ofthe binary system, and to allow a safe comparison with theoreticalisochrones for single stars. Such a comparison suggests that theprogenitor of the outbursting component had an initial mass ~65M_ȯ, that it was approaching the carbon ignition stage in its coreat the time it erupted in 2002 and that the age of the V838 Mon binarysystem is close to 4 million yr. The 2002 event is probably just a shellthermonuclear event in the outer envelope of the star.
| Open clusters in the third galactic quadrant. I. Photometry
We have performed a photometric survey of open clusters in the thirdGalactic quadrant in order to study the star formation history andspatial structure in the Canis Major-Puppis-Vela region. In this paperwe describe a catalogue of CCD U BV RI photometry of approximately 65000 stars in the fields of 30 open clusters. The data were obtained andreduced using the same telescope, the same reduction procedures, and thesame standard photometric system, which makes this catalogue the largesthomogeneous source of open cluster photometry so far. In subsequentpapers of this series, colour-colour and colour-magnitude diagrams willbe presented which, amongst other uses, will allow the determination ofan homogeneous set of cluster reddenings, distances, and ages that willconstitute the observational basis for our studies of the spatialstructure and star formation history in the third Galactic quadrant.
| CCD photometry of the galactic open cluster NGC 2309
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| A report on the studies of star clusters with the UPSO 104-cm Sampurnanand telescope during last 25 years
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