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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Optimal photometry for colour-magnitude diagrams and its application to NGC 2547
We have developed the techniques required to use Naylor's optimalphotometry algorithm of to create colour-magnitude diagrams withwell-defined completeness functions. To achieve this we firstdemonstrate that the optimal extraction is insensitive to uncertaintiesin the measured position of the star. We then show how to correct theoptimally extracted fluxes such that they correspond to those measuredin a large aperture, so aperture photometry of standard stars can beused to place the measurements on a standard system. The techniquesimultaneously removes the effects of a position-dependent point spreadfunction. Finally, we develop a method called `ghosting', whichcalculates the completeness corrections in the absence of an accuratedescription of the point spread function. We apply these techniques tothe young cluster NGC 2547 (=C0809-491), and use an X-ray-selectedsample to find an age of 20-35 Myr and an intrinsic distance modulus of8.00-8.15 mag. We use these isochrones to select members from ourphotometric surveys. Our derived luminosity function shows awell-defined Wielen dip, making NGC 2547 the youngest cluster in whichsuch a feature has been observed. Our derived mass function spans therange 0.1-6 Msolar and is similar to that for the field andthe older, more massive clusters M35 and the Pleiades, supporting theidea of a universal initial mass function.
| 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
| 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.
| The VELA star cloud. III - The B8 to A0 stars and interstellar reddening
The present discussion of intermediate band and H-beta observations of360 HD stars B8-A0 in Vela, and all of the CPD stars in a small adjacentregion, notes that the interstellar absorption in both cases can beunderstood as a combination of three absorbing clouds of 1 kpc-A(V) =1.5, 0.5, and 0.17. The major difference in the two environments is thepresence of numerous T Tauri stars in Taurus. Several clusters in theVela region are discussed.
| Uvby-beta photometry of southern clusters. VII - NGC 2547
Stromgren four-color and beta photometry has been obtained for the 13brightest members of the young galactic cluster NGC 2547. The data aregenerally in good agreement with other photometry for these stars andthe mean distance modulus obtained from several methods, including theBalona and Shobbrook (1984) beta/c0/M(V) calibration for B stars, is8.1.
| The common origin of some open clusters
Eight open clusters have been observed with uvby-beta photometry and forseven of them the metal abundances have been determined. Six of thesehave similar metallicities. They are close in space and are also knownto have similar ages and radial velocities. These clusters are suspectedof having a common origin. Some studies are made of the reliability ofthe photometric system. A large gain in limiting magnitude can beachieved against an unimportant loss of accuracy if interference filtersare removed.
| Membership Basic Parameters and Luminosity Function of the Southern Open Cluster NGC2547
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1982A&AS...47..323C&db_key=AST
| The VELA star cloud. I - NGC 2547, TR 10, the Gamma Velorum system, and bright stars
The first results of an intermediate-band, large-scale photometricsurvey of the Vela star cloud are discussed. Attention is given to theluminosity and reddening, as well as the apparent or proper motions ofall the CPD stars near NGC 2547, the brightest stars in Trumpler 10, arandom selection of stars in the region of Gamma Velorum, and the HRstars. The similarity of the Alpha Persei cluster with the clusters inthe Vela sheet is shown, and it is found that the Vela sheet, at leastover the region surveyed, is nearly perpendicular to the line of sight.The probability is demonstrated that a thin sheet of coeval (2.5 x 10 tothe 7th yr) stars, some 425 pc distant and with a similar metalabundance, lies in front of a dense dark cloud.
| 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
| Proper Motions, Radial Velocities and Star Counts in NGC 2547
Not Available
| Photoelectric Magnitudes and Colours in NGC 2547
Not Available
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Membre dels grups següents:
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Dades d'Observació i Astrometria
| Constel·lació: | Vela |
| Ascensió Recta: | 08h09m59.22s |
| Declinació: | -49°16'10.9" |
| Magnitud Aparent: | 8.131 |
| Distancia: | 295.858 parsecs |
| Moviment propi RA: | -7 |
| Moviment propi Dec: | 3.7 |
| B-T magnitude: | 8.125 |
| V-T magnitude: | 8.131 |
Catàlegs i designacions:
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