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CCD BV survey of 42 open clusters
Aims.We present results of a photometric survey whose aim was to derivestructural and astrophysical parameters for 42 open clusters. While oursample is definitively not representative of the total open clustersample in the Galaxy, it does cover a wide range of cluster parametersand is uniform enough to allow for simple statistical considerations. Methods: BV wide-field CCD photometry was obtained for open clusters forwhich photometric, structural, and dynamical evolution parameters weredetermined. The limiting and core radii were determined by analyzingradial density profiles. The ages, reddenings, and distances wereobtained from the solar metallicity isochrone fitting. The mass functionwas used to study the dynamical state of the systems, mass segregationeffect and to estimate the total mass and number of cluster members. Results: This study reports on the first determination of basicparameters for 11 out of 42 observed open clusters. The angular sizesfor the majority of the observed clusters appear to be several timeslarger than the catalogue data indicate. The core and limiting clusterradii are correlated and the latter parameter is 3.2 times larger onaverage. The limiting radius increases with the cluster's mass, and boththe limiting and core radii decrease in the course of dynamicalevolution. For dynamically not advanced clusters, the mass functionslope is similar to the universal IMF slope. For more evolved systems,the effect of evaporation of low-mass members is clearly visible. Theinitial mass segregation is present in all the observed young clusters,whereas the dynamical mass segregation appears in clusters older thanabout log({age}) = 8. Low-mass stars are deficient in the cores ofclusters older than log({age}) = 8.5 and not younger than one relaxationtime.Tables 1-5 are only available in electronic form at http://www.aanda.org
| 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
| HD 172189: an eclipsing and spectroscopic binary with a δ Sct-type pulsating component in an open cluster
We present a study based on more than 2500 uvby-measurements collectedon HD 172189, a new eclipsing binary system with a δ Sct-typepulsating component that belongs to the open cluster IC 4756. The greatinterest of this object lies in that three important characteristicscoexist: cluster membership, binarity and pulsation. Its binarity andthe δ Sct-type pulsations of one component were detected in thecourse of several Strömgren photometric campaigns. The frequencyanalysis of all the uvby out-of-eclipse data reveals a clear frequencyof 19.5974 cd-1as well as the existence of other high valuesin the range 18-20 cd-1. We have also carried out a firstevaluation of the binary parameters and determined a value of 5.702 dfor the orbital period. An additional potential interest of HD 172189resides in its location in the field of view of the COROT mission and,therefore, this star is an excellent candidate for becoming a target forasteroseismology.
| Collaborative Research of Open Star Clusters
Preliminary results on observations of open clusters are pre-sented. Theproject has been initiated in the framework of the Uzbek-Taiwan andTaiwan-Baltic collaboration, mainly to upgrade and make use offacilities at Maidanak Observatory. We present detailed,multi-wavelength studies of the young cluster NGC 6823 and theassociated complex nebulosity, to diagnose the young stellar populationand star formation history in the region. In addition, 7 compact openclusters have been monitored for stellar variability. We show howobservations like these could feasibly be used to look for exoplanettransit events. We also expect to join the Whole-Earth Telescope effortin future campaigns for asteroseismology.
| The first CCD photometric study of the open cluster NGC 2126
We present the first CCD photometric observations of the northern opencluster NGC 2126. Data were taken on eight nights in February andDecember 2002 with a total time span of ~ 57 hours. Almost 1000individual V-band frames were examined to find short-period variablestars. We discovered six new variable stars, of which one is a promisingcandidate for an eclipsing binary with a pulsating component. Two starswere classified as delta Scuti stars and one as Algol-type eclipsingbinary. Two stars are slow variables with ambiguous classification. Fromabsolute V(RI)C photometry we have estimated the maincharacteristics of the cluster: m-M=11fm0 +/-0fm5 , E(V-I)=0fm4 +/-0fm1, E(V-R)=0fm08 +/-0fm06 (E(B-V)=0fm2 +/-0fm15 ) and d=1.3+/-0.6 kpc.Cluster membership is suggested for three variable stars from theirpositions on the colour-magnitude diagram.
| Liste des étoiles Ap et Am dans les amas ouverts (Edition révisée)
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| Catalog of AP and AM stars in open clusters
The previous results of Raab (1922), Markarian (1951), and Collinder(1931) have been used to catalog Ap and Am stars that are in the fieldof open clusters. Tabular data are presented for the clusterdesignation, the HD or HDE number, the right ascension (1900), thedeclination (1900), and the magnitude. Also listed are the spectraltypes and, for certain stars, the probability of cluster membership.
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| The Galactic Cluster NGC 2126 and NGC 2194.
Abstract image available at:http://adsabs.harvard.edu/abs/1943ApJ....97...93C
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