A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
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Kinematics and binaries in young stellar aggregates. II. NGC 6913 ≡ M 29
Between 1996 and 2003 we obtained 226 high resolution spectra of 16stars in the field of the young open cluster NGC 6913, to constrain itsmain properties and study its internal kinematics. Twelve of the programstars turned out to be members, one of them probably unbound. Nine arebinaries (one eclipsing and another double lined) and for seven of themthe observations allowed us to derive the orbital elements. All but twoof the nine discovered binaries are cluster members. In spite of theyoung age (a few Myr), the cluster already shows signs that could beinterpreted as evidence of dynamical relaxation and mass segregation.However, they may be also the result of an unconventional formationscenario. The dynamical (virial) mass as estimated from the radialvelocity dispersion is larger than the cluster luminous mass, which maybe explained by a combination of the optically thick interstellar cloudthat occults part of the cluster, the unbound state or undetected verywide binary orbit of some of the members that inflate the velocitydispersion and a high inclination for the axis of possible clusterangular momentum. All the discovered binaries are hard enough to surviveaverage close encounters within the cluster and do not yet show signs ofrelaxation of the orbital elements to values typical of field binaries.Table 2 is only available in electronic form athttp://www.edpsciences.orgTable 4 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/415/145
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New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
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Spectroscopic orbit of the eclipsing binary V2031 Cyg in the field of the open cluster NGC 6913=M 29
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CCD uvbybeta photometry of young open clusters. I. The double cluster h and chi Persei
We present CCD uvbybeta photometry for stars in the nuclei of the youngdouble cluster h and chi Persei. We find that the reddening is highlyvariable through the h Per nucleus, increasing from west to east, withvalues ranging from E(b-y) = 0.328+/-0.022 in the western part to E(b-y)= 0.465+/-0.024 in the south-east. Towards chi Per the reddening isfairly constant, with E(b-y) = 0.398+/-0.025. Both clusters share acommon distance modulus of 11.7+/-0.1 mag, and an age of log t =7.10+/-0.05 years. Tables 6 and 7 are only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/394/479
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Vilnius Photometry and Reddening of the Young Open Cluster NGC 6913
87 stars in the NGC 6913 field with both UBV and Vilnius photometry areselected to be the sample. The membership probability of the stars isgreater than 50%. The correlation among Vilnius photometry, UBVphotometry and reddening in the cluster is reviewed. It is found thatthe photometry in the Vilnius X, Y and Z bands can be used to make roughspectral classification. The values of E(B-V) are well correlated withthe Vilnius colors of X-Y, Y-Z, Z-V and V-S in NGC 6913. The ratio of(V-S)/(Y-Z) of the MPCM (Most Possible Cluster Members) is a constant(1.30 ~ ± 0.06), and has no effect on the values of E(B-V), (B-V)_0and V_0. Comparing with the observational data of all the stars of NGC6913 region, we propose that the value of (V-S)/(Y-Z) can probably beused to select the preliminary candidates of one open cluster. Inaddition, 12 variable stars are discovered in the NGC 6913 region, inwhich star #155 has a variation with an amplitude of 4.25 mag.
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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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Spectral classification and reddening in the young open cluster NGC 6913
Spectroscopic observations have been made for the young open cluster NGC6913. In total, the spectra of 100 stars of the cluster, havingmembership probability greater than 50%, have been obtained andclassified. Reddening is estimated on the basis of spectralclassification. The variable extinction across NGC 6913 is analyzed anddiscussed. From the spectroscopic observations, it is found that thespectral type distribution in our sample covers from O7 to K3. There areonly 2 O-type stars in this OB association. 40 and 33 percent of thetotal stars are B and A type stars respectively, and the F, G, K starsamount to 25 percent. An extreme variation of extinction is found acrossthe young open cluster NGC 6913. The distribution of extinction in theregion is correlated with the effective temperature of the stars forstars earlier than F8. It is found that extinction in the cluster centeris relatively homogeneous, but very large. The north and south of thiscluster have the largest extinction. The eastern and western parts seemto be low reddening regions. A mean distance modulus of 10.17+/-0.14mag. is derived for the cluster, which corresponds to a distance of 1.08kpc. A large part of the values of interstellar reddening of the starsin NGC 6913 from spectral classification are quite different from thosetaken from photometry (especially for early B and F type stars); thelargest discrepancy amounts to 1.48 mag.. Depending on a reddeningmethod, a total amount of 30% of the stars with membership probabilitygreater than 50% can be evaluated to be probable ``non-members" of thecluster. In addition, some interesting objects are found in this study.Further observations for these stars will be made in the future.
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The 73rd Name-List of Variable Stars
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Classification of Population II Stars in the Vilnius Photometric System. II. Results
The results of photometric classification of 848 true and suspectedPopulation II stars, some of which were found to belong to Population I,are presented. The stars were classified using a new calibrationdescribed in Paper I (Bartkevicius & Lazauskaite 1996). We combinethese results with our results from Paper I and discuss in greaterdetail the following groups of stars: UU Herculis-type stars and otherhigh-galactic-latitude supergiants, field red horizontal-branch stars,metal-deficient visual binaries, metal-deficient subgiants, stars fromthe Catalogue of Metal-deficient F--M Stars Classified Photometrically(MDPH; Bartkevicius 1993) and stars from one of the HIPPARCOS programs(Bartkevicius 1994a). It is confirmed that high galactic latitudesupergiants from the Bartaya (1979) catalog are giants or even dwarfs.Some stars, identified by Rose (1985) and Tautvaisiene (1996a) as fieldRHB stars, appear to be ordinary giants according to our classification.Some of the visual binaries studied can be considered as physical pairs.Quite a large fraction of stars from the MDPH catalog are found to havesolar metallicity. A number of new possible UU Herculis-type stars, RHBstars and metal-deficient subgiants are identified.
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HD 194378 - a New Eclipsing Binary in the Open Cluster M29 (= NGC6913)
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The Initial Mass Function and Massive Star Evolution in the OB Associations of the Northern Milky Way
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...454..151M&db_key=AST
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Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
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The 71st Name-List of Variable Stars
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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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Photoelectric Photometry of Stars in the Vilnius System in the Region of the Open Cluster NGC6913 = M29
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Photometry of the open cluster NGC 6913
Photoelectric UBV magnitudes and colors have been determined for 103stars in the field of NGC 6913. The reddening across the cluster isvariable. The distance modulus to the cluster is estimated at 10.85 + or- 0.15 mag. It is found that cluster stars have ages between 0.3 and1.75 Myr.
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Four-color and H-beta photometry of open clusters. XII - NGC 6910 and NGC 6913
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977AJ.....82..606C&db_key=AST
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Variable Stars in the Galactic Cluster NGC 6913
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Membership of the open cluster NGC 6913 (M29)
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS....9..221S&db_key=AST
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La mesure des vitesses radiales au prisme objectif. XV. 7e liste de vitesses radiales déterminées au prisme obtif à vision directe
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Structure de la galaxie dans la région de P Cygni
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Photometry of stars in galactic cluster fields.
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A System of Three-Color Photometry, with applications to Galactic Structure in Cygnus
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958AJ.....63..127T&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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INHABITED SKY
