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Spectroscopic Binaries and Kinematic Membership in the Open Cluster NGC 3532
We report spectroscopic observations for bright stars in the opencluster NGC 3532 up to 1 mag below the turnoff point. We compute radialvelocities by cross-correlations and determine spectral types androtational velocities. Using 21 stars identified as certain members, wederive a mean cluster velocity of +3.4+/-0.3 km s-1. Fromradial velocities and angular distances to the cluster center, wecompute membership probabilities for all but two stars that are radialvelocity variables. Only one out of 34 program stars is a clearkinematic nonmember. Three spectroscopic binaries and three additionalpossible radial velocity variables are detected among the 23 starsmeasured more than once. We report the star HD 96609 as a double-linedspectroscopic binary. Using the two-dimensional cross-correlationtechnique TODCOR developed by Zucker & Mazeh, we derive the radialvelocity curves for both components and obtain the orbital parameterswith errors of 0.3% and 0.7% for the projected orbital semiaxis andmasses, respectively. This system is composed of two main-sequence starsin a circular orbit, with a period of 8.19 days. The observationspresented here were obtained at the Complejo Astronómico ElLeoncito (CASLEO), which is operated under agreement between the ConsejoNacional de Investigaciones Científicas y Técnicas de laRepública Argentina (CONICET) and the National Universities of LaPlata, Córdoba, and San Juan.
| Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Open clusters with Hipparcos. I. Mean astrometric parameters
New memberships, mean parallaxes and proper motions of all 9 openclusters closer than 300 pc (except the Hyades) and 9rich clusters between 300 and 500 pc have been computed using Hipparcosdata. Precisions, ranging from 0.2 to 0.5 mas for parallaxes and 0.1 to0.5 mas/yr for proper motions, are of great interest for calibratingphotometric parallaxes as well as for kinematical studies. Carefulinvestigations of possible biases have been performed and no evidence ofsignificant systematic errors on the mean cluster parallaxes has beenfound. The distances and proper motions of 32 more distant clusters,which may be used statistically, are also indicated. Based onobservations made with the ESA Hipparcos astrometry satellite
| The calibration of the Stromgren photometric system for A, F and early G supergiants. I - The observational data
An empirical calibration of the Stromgren uvby-beta photometric systemfor the A, F, and early G supergiants is being derived. This paperexplains the observational program and the photometric reductiontechniques used and presents a catalog of new Stromgren photometry forover 600 A, F, and G supergiants.
| The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotation
The MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars.
| Photoelectric search for CP2-stars in open clusters. XI - NGC 3532 and NGC 5662
Delta-a photometry was carried out for 164 stars in NGC 3532 (the mostpopulous cluster studied so far in this series) and 27 stars in NGC5662. Surprisingly, only one mildly peculiar star (Koelbloed 232) wasidentified this way among the roughly hundred cluster members of NGC3532. Three photometrically peculiar objects were found among theapproximately 60 field stars in the cluster area. This is about theaverage frequency of CP2-stars, in contrast to the pronounced shortageof CP2-stars in the rather old cluster NGC 3532. In NGC 5662 twoCP2-objects, MV6 and MV10, were identified. MV6, however, is a probablenonmember based on its proper motion data. As in some previous casesagain a negative Delta-a object was found with reportedBe-characteristics (NGC 5662-MV29).
| Stromgren photometry of open clusters. II - NGC3532
Stromgren photometry of B- and A-type stars in the southern open clusterNGC3532 up to V = 11.5 mag is presented. The membership of the observedstars is discussed and a reddening of E(b-y) = 0.025 for the cluster isestimated. Also, the occurrence of chemically peculiar early type (CP1and CP2) stars is examined.
| UBVRI photometry in the open cluster NGC 3532
NGC 3532 is a populous open cluster of intermediate age located a fewdegrees northwest of Eta Carina. The present investigation is concernedwith observations which were conducted at the Las Campanas Observatoryin Chile during the period March-July 1981. A 61-cm telescope and UBVRIphotometer system described by Fernie (1974) were used in theobservations. The results for the cluster stars are listed in a table.Standard stars from the E regions of Cousins were used each night tocarefully determine extinctions and transformations. Attention is givento nightly rms errors for Cousins standards, the B-V color-magnitudediagram for NGC 3532, a V-R color-magnitude diagram for NGC 3532, andcomparisons of V magnitudes and B-V colors for NGC 3532
| The open cluster NGC 3532
NGC 3532 is a large cluster in the Carina region of the southern MilkyWay. Observations in the modified Stromgren and H beta systems have beenobtained for 33 stars. (R,I) photometry for the red stars is listed in atable. The HD and CPD numbers for the 33 stars are also listed togetherwith the numbers assigned by Koelbloed. Attention is given to reddeningand luminosity determinations, the red giants in the cluster region, acomparison of computed and cluster luminosities for some of thecalibrating stars, and age considerations. It is pointed out that theusefulness of NGC 2287 and 3532 for testing stellar models is increasedby the existence of a third, bright cluster of intermediate age, NGC6475.
| Photometric Study of the Southern Open Cluster NGC3532
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...39...11F&db_key=AST
| The frequency of peculiar A and metallic-line stars in open clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJ...205..807H&db_key=AST
| Three-colour photometry of the three southern open clusters NGC 3532, 6475 (M7), and 6124
Not Available
| Photovisual magnitudes of 219 stars in NGC 3532
Not Available
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