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HD 20023


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uvby - β Photoelectric Photometry of the Open Cluster α Per
Absolute photoelectric photometry of stars in the direction of the OpenCluster α Per has been secured and is presented along with ananalysis reinforced with all the available data in Strömgrenuvby-β photometry compiled from the literature. Cluster membershipis analyzed and the physical characteristics of the stars have beendeduced. The membership determined in this paper is compared with thatof proper motion studies and Hipparcos.

Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available

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

Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm

A new library of stellar optical spectra
Attention is given to a new digital optical stellar library consistingof spectra covering 3510-8930 R at 11-A resolution for 72 differentstellar types. These types extend over the spectral classes O-M andluminosity classes I-V. Most spectra are of solar metallicity stars butsome metal-rich and metal-poor spectra are included. This new library isquantitatively compared to two previously published libraries. It offersseveral advantages over them: it is photometrically well-calibratedindividually and consistently from star to star. Good temperature andluminosity coverage has been achieved. The incorporation of stars withwell-determined temperature, metallicity, and surface gravity parametersincreases the accuracy of the spectral type assigned to each compositelibrary star.

Halo blue horizontal branch stars - Spectroscopy in two fields
Results are presented of spectroscopic observations at 2-A resolution of44 stars in two fields. A total of 39 are identified as blue horizontalbranch (BHB) stars, RR Lyrae, or main-sequence A stars. The candidateswere selected by color from digitized UK Schmidt direct plates and bythe presence of a strong Balmer discontinuity in their objective prismspectra. Velocities and distances are measured for each of the BHBcandidates. At moderate spectral dispersion the distinction betweenmain-sequence A stars and horizontal branch stars cannot be made on thebasis of hydrogen linewidths alone. Four stars at a distance of 30 kpcin one field are found to have a velocity dispersion of less than 12km/s, and a systematic velocity of 70 km/s with respect to the Galacticrest frame. These stars are not bound to each other but may be thestellar remnants of a recently disrupted halo cluster.

A library of stellar spectra
Spectra for 161 stars having spectral classes O-M and luminosity classesV, III, and I have been incorporated into a library available onmagnetic tape. The spectra extend from 3510 to 7427 A at a resolution ofabout 4.5 A. The typical photometric uncertainty of each resolutionelement in the spectra is on the order of 1 percent while broad-bandvariations are smaller than 3 percent. Potential uses for the libraryinclude population synthesis of galaxies and clusters, tests of stellaratmosphere models, spectral classification, and the generation of colorindices having arbitrary wavelength and bandpass.

Distance Moduli of Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965ApJS...12..215H&db_key=AST

L'ammasso galattico NGC 1245
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Eigenbewegungen in der Umgebung von α Persei
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Observation and Astrometry data

Constellation:Περσεύς
Right ascension:03h14m50.64s
Declination:+47°09'18.2"
Apparent magnitude:7.937
Distance:307.692 parsecs
Proper motion RA:-2.9
Proper motion Dec:-8
B-T magnitude:7.966
V-T magnitude:7.94

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 20023
TYCHO-2 2000TYC 3315-725-1
USNO-A2.0USNO-A2 1350-03206593
HIPHIP 15105

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