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.
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Beryllium Abundances in F and G Dwarfs in the Pleiades and α Persei Clusters from Keck High-Resolution Echelle Spectrometer Observations
While there are many observations of Li in open clusters, there are veryfew of the companion light element Be. As we have seen in the study ofBe in the Hyades by Boesgaard & King, the two elements togetherprovide important and unique information on the extent and nature ofinterior mixing in solar-like stars. We have obtained high-resolution(45,000) spectra of the Be II resonance lines in the 14 Pleiades andfour α Per dwarfs of spectral types F and G with the Keck Itelescope and High-Resolution Echelle Spectrometer. The signal-to-noiseratio in the Be spectral region is typically 40 pixel-1.These two clusters have similar ages and have solar metallicity.Abundances of Be were determined by spectrum synthesis using the newestversion of MOOG. For the F dwarfs where there is only a weak Li dip,there is no indication of a Be dip as was found in the Hyades inassociation with its deep Li dip. Thus, the observed light elementdepletion in the F dwarfs in the Hyades and in field stars is occurringduring main-sequence evolution, and Be depletion does not become evidentuntil ages of more than 100 Myr. The Pleiades G dwarfs are apparentlyundepleted in Be and the mean value for logN(Be/H)+12.00 in stars coolerthan 6000 K is 1.26+/-0.10, compared to the Hyades mean of 1.31+/-0.07.The star-to-star dispersion in Be in the Pleiades is comparable to thequoted errors. The four α Per stars have lower Be abundances thanthe Pleiades with a mean of 1.02 dex. The differences in these twoclusters in their Li and Be abundances relative to the Hyades is thoughtto be due to their younger age and possibly their lower metallicity.
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Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
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A catalogue of [Fe/H] determinations: 1996 edition
A fifth Edition of the Catalogue of [Fe/H] determinations is presentedherewith. It contains 5946 determinations for 3247 stars, including 751stars in 84 associations, clusters or galaxies. The literature iscomplete up to December 1995. The 700 bibliographical referencescorrespond to [Fe/H] determinations obtained from high resolutionspectroscopic observations and detailed analyses, most of them carriedout with the help of model-atmospheres. The Catalogue is made up ofthree formatted files: File 1: field stars, File 2: stars in galacticassociations and clusters, and stars in SMC, LMC, M33, File 3: numberedlist of bibliographical references The three files are only available inelectronic form at the Centre de Donnees Stellaires in Strasbourg, viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5), or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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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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A catalogue of Fe/H determinations - 1991 edition
A revised version of the catalog of Fe/H determinations published by G.Cayrel et al. (1985) is presented. The catalog contains 3252 Fe/Hdeterminations for 1676 stars. The literature is complete up to December1990. The catalog includes only Fe/H determinations obtained from highresolution spectroscopic observations based on detailed spectroscopicanalyses, most of them carried out with model atmospheres. The catalogcontains a good number of Fe/H determinations for stars from open andglobular clusters and for some supergiants in the Magellanic Clouds.
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Membership of low-mass stars in the open cluster Alpha Persei
The results of a combined astrometric, photometric, and spectroscopicsearch for low-mass members in the intermediate-age open cluster AlphaPersei are presented. Over 130 low-mass new members have been identifiedto M(v) about 12.5, almost doubling the previous number of knownmembers. The new membership information suggests a slight upwardrevision of Alpha Per's age to about 8 x 10 exp 7 yr. Alpha Per isnoticeably spatially elongated in a direction parallel to the Galacticplane, most likely due to tidal deformation. Analysis of thedistribution of relative H-alpha emission strengths among Alpha Permembers confirms the view that the mean H-alpha strength decreases inincreasingly older systems. Allowing for survey incompleteness, onecannot reject the idea that the luminosity function is consistent withthe field luminosity function to M(v) about 9 or 10.
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Metallicity in galactic clusters from high signal-to-noise spectroscopy
High-quality spectroscopic data on selected F dwarfs in six Galacticclusters are used to determine global (Fe/H) values for the clusters.For the two youngest clusters, Pleiades and Alpha Per, the (Fe/H) valuesare solar: 0.017 + or - 0.055. The Hyades and Praesepe are slightlymetal-enhanced at (Fe/H) = + 0.125 + or - 0.032, even though they are anorder of magnitude older than the Pleiades. Coma and the UMa Group atthe age of the Hyades are slightly metal-deficient with (Fe/H) = - 0.082+ or - 0.039. The lack of an age-metallicity relationship indicates thatthe enrichment and mixing in the Galactic disk have not been uniform ontime scales less than a billion years.
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Lithium in lower-main-sequence stars of the Alpha Persei cluster
Lithium abundances are presented for main-sequence stars of spectraltypes F, G, and K in the young open cluster Alpha Per. For 46 clustermembers, a correlation between Li abundance and projected rotationalvelocity v sin i is found: all of the Li-poor stars are slow rotators.Two explanations are proposed to account for the correlation: (1) thatthe Li depletion is introduced following a rapid spin-down phaseexperienced by young low-mass stars, and that this episode of Lidepletion may be the dominant one determining the spread of Liabundances among young low-mass main-sequence stars, and (2) that starformation has occurred over a finite period such that the older starshave undergone a spin-down and depletion of Li by a means that may ormay not depend on rotation. The Li abundance in the warm and rapidlyrotating stars appears to be undepleted, as is predicted by recentmodels of pre-main-sequence stars. The depletion observed in the coolstars exceeds the level predicted by these models.
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Lithium in the Pleiades and Alpha Persei clusters
Observations of the Li region in the 23 F dwarfs of the Pleiades andAlpha Per clusters were performed with a TI CCD at the coudespectrographof the 200-inch telescope with a spectral resolution of 0.2 A and 2sigma signal-to-noise ratios of 100-300. All 21 of the stars observed inthe temperature region of 6100-7300 K show strong Li I lines with valuesof log N(Li) near 3.0; the mean is 2.98 + or - 0.13. The data suggestthat the significant decrease in surface Li, possibly caused bydiffusion or differential rotation, occurs for cluster stars between theages of 5 x 10 to the 7th to 5 x 10 to the 8th yr.
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Spectral types in the alf Per cluster.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978PASP...90..692A&db_key=AST
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Four-color and H beta photometry for open clusters. 10. The alf Per cluster.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79..687C&db_key=AST
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The H-R diagram of the alf Per cluster.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971AJ.....76..242M&db_key=AST
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The radial velocities., luminosities of 77 stars in the field of the alf Per cluster.
Not Available
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Studies of Stellar Rotation.IV. a Comparison of Rotational Velocities in the Alpha Persei Cluster and the Pleiades
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1967ApJ...148..129K&db_key=AST
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Mesures d'étoiles doubles faites au rĝfraceur de 38 cm de l'Observatoire de Nice
Not Available
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Photometry of the α Persei Cluster.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960ApJ...132...68M&db_key=AST
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Das Farben-Helligkeits-Diagramm des Bewegungshaufens um Alpha Persei. Mit 5 Textabbildungen
Not Available
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Eigenbewegungen in der Umgebung von α Persei
Not Available
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INHABITED SKY
