Pulkovo compilation of radial velocities for 35495 stars in a common system.
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The young open cluster NGC 663 and its Be stars
We present new BV(RI)CHα photometry of the young opencluster NGC 663. The Hα photometry is complete down to magnitudeRC = 15.4, corresponding to spectral type A5 for the clustermembers. This allows detection of mild and strong Hα emission inall B-type stars in the cluster. In addition to the 22 Be stars known inthe observed field of NGC 663, we discovered four new faint stars ofthis type. We find that Be stars in NGC 663 cover the whole range of theB spectral type. They are, however, most populous among stars withspectral types falling in the range between B0 and B3, where theirfraction amounts to 31 +/- 8%. Among B-type stars later than B3, Bestars are much less abundant: only 7 out of 101 observed stars, that is,7 +/- 3%, were detected. About 70% of the observed Be stars in NGC 663show detectable variations of light. In the time interval covered by ourobservations, the ranges of the largest variations reach 0.4 mag in theIC band. By means of the isochrone fitting, we derived thecluster distance of 2.1 kpc, age of 20-25 Myr, and the mean colourexcess E(R-I)C = 0.54 mag, with a ~ 0.1 mag scatter due todifferential reddening. Tables 2 and 3 are only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/376/144
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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
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Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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Catalogue of stars in the northern Milky Way having H-alpha in emission
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Near-infrared and Stromgren photometry of the open clusters NGC 663, NGC 1502 and NGC 1893
Observational data are presented regarding the three objects includingnear-IR JHK, Stromgren uvby, and H-beta photometry of the centralregions. The intrinsic photometric colors of average main-sequence starsare taken from previous studies to examine the data with m1 vs. b-y, c1vs. m1, beta vs. c1, J-H vs. H-K, and V-K vs. b-y diagrams. It isdetermined that the ages of and distance to NGC 663, NGC 1502, and NGC1893 are respectively 9 x 10 exp 6 yr and 2.5 kpc, 5 x 10 exp 6 yr and1.5 kpc, and 4 x 10 exp 6 yr and 4.3 kpc. The results indicate otherparameters, and considerable differental reddening is noted across NGC663. The total-to-selective extinction ratio is also examined showingthat it is smaller than the galactic value towards NGC 663 and 1893 andsignificantly lower than the average value for the ISM in NGC 1502. Itis concluded that the size distribution of the dust particles in thepresent line-of-sight has an inherent bias.
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More radial-velocity measurements in young open clusters
Further high resolution radial-velocity measurements are reported in 23young open clusters using the Kitt Peak CCD coude spectrograph on the0.9-m feed telescope. The radial velocities for the cluster stars arederived with the technique of cross correlation. The internal precisionof the velocity measurements is typically 2 km/s for early type stars.From these new data and previously published velocities, the observedstars in two clusters, NGC 663 and NGC 2287, were found to show arelatively small dispersion in the measured mean velocities. Furtherobservations of stars in young clusters will be useful in helping toestablish an early-type-star-velocity standard system.
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Radial-velocity measurements in 20 young open clusters
The further results of a program to determine the radial velocities ofyoung open clusters are presented. Using the KPNO coude spectrographcoupled with the 1-m feed and 2.1-m telescopes, radial velocities havebeen measured for nearly one hundred stars, most of which are ofspectral type B and A, in 20 young clusters. The combination ofinstruments and the use of cross-correlation techniques show that radialvelocities of B and A type stars as faint as 10th magnitude can bedetermined with an internal precision of less than about 2 km/s. Asexpected, the uncertainties in the velocity determination for the youngclusters are dominated by spectroscopic binary stars in these clusters.A third of the stars in the sample are found to be spectroscopicbinaries, but with a large variation in the frequency of binaries fromcluster to cluster. Because the time coverage is still limited, thisshould be considered a lower limit to the binary frequency. Clustervelocities are determined after eliminating binaries and known nonmemberstars. The new velocities are compared with a model galactic rotationcurve, as well as with previous velocity determinations.
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Chemically peculiar stars in open clusters. I - The catalog
The largest existing compilation is presented of Ap and Am open clusterstars. The catalog contains information on 381 chemically peculiar (CP)stars of the upper main sequence in 79 open clusters. The catalog iscomposed of the following tables: (1) the main body, which lists CP (orsuspected CP) stars which are kinematical (or suspected kinematical)members of open clusters; (2) the list of CP (or suspected CP) starssometimes numbered among cluster members but which are actuallykinematical nonmembers; (3) the list of stars sometimes designated as'peculiar' but, in fact, probably not CP; (4) references for numberingsystems of cluster stars; (5) references for membership; and (6)references for spectral and/or peculiarity types.
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Be stars in open clusters
Rotational velocities and spectral types have been determined for Bestars in 12 open clusters in both the northern and the southern sky, andcolor-magnitude or H-R diagrams constructed for each from availablephotometric data. The location of the Be stars in the color-magnitudediagrams shows again that Be stars may exist in various evolutionarystages, including the essentially unevolved stage. Although many Bestars are considerably off the zero-age main sequence, it does notnecessarily follow that these are in the core-contraction stage becausecircumstellar reddening and rotationally induced gravity darkening ofthe underlying star will also move stars to the right of the mainsequence in a colormagnitude diagram. The evolutionary status of Bestars seems still to be quite uncertain.
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The emission-line stars in NGC 663
The young galactic cluster NGC 663 has been observed on a series ofobjective-prism plates obtained during the period from 1946 to 1975, inorder to establish the percentage of Be stars in this cluster and todetermine the frequency of 27 H-alpha emission-line variables. Theresults indicate that H-alpha emission is firmly established in 18 starsreported in more than one independent survey, that the Be stars areconfined to spectral types B5 and earlier, and that at least one-thirdof the early B-type cluster members have exhibited Be characteristics atone time or another. It is also found that large-amplitude variations inthe strength of the H-alpha emission occurred during the three-decadeinterval in one-third of the Be stars on a time scale of several years.A color-magnitude diagram is plotted for the confirmed emission-line inNGC 663.
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UBV Photometry of the Open Cluster NGC 663
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978AJ.....83.1075V&db_key=AST
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The space distribution and radial velocities of some early-type stars in the Perseus spiral arm
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79..597M&db_key=AST
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Photographische UBV-Helligkeiten in 14 jungen Sternhaufen der nordlichen Milchstrasse.
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NGC 663.
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Distance Moduli of Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965ApJS...12..215H&db_key=AST
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Galactic structure in Cassiopeia.
Abstract image available at:http://adsabs.harvard.edu/abs/1964AJ.....69..412M
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Photometry of stars in galactic cluster fields.
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La mesure des vitesses radiales au prisme objectif. IX - 3e liste de vitesses radiales déterminées au prisme objectif à vision directe
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Der galaktische Sternhaufen NGC 663.
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Stellar Spectra and Colors in a Milky way Region in Cassiopeia.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJS....2..123F&db_key=AST
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Drei-Farben-Photometrie von 11 offenen Sternhaufen, insbesondere solchen mit O-und frühen B-Sternen. Mit 21 Text-abbildungen
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Kolorimetrische Untersuchungen an offenen Sternhaufen in den Standrd-Spektralbereichen der Integralphotometrie. Ngc 663
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An investigation of color excess in galactic star clusters
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A photometric research on two open clusters in Cassiopeia.
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A study of proper motions in the cluster NGC 663
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