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Spectral Classification of Stars in A Supplement to the Bright Star Catalogue
MK spectral types are given for about 584 stars in A Supplement to theBright Star Catalogue. These are compared with Hipparcos parallaxes tocheck the reliability of those classifications. The estimated errors are+/-1.2 subtypes, and 10% of the luminosity classes may be wrong.
| The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of 14 000 F and G dwarfs
We present and discuss new determinations of metallicity, rotation, age,kinematics, and Galactic orbits for a complete, magnitude-limited, andkinematically unbiased sample of 16 682 nearby F and G dwarf stars. Our63 000 new, accurate radial-velocity observations for nearly 13 500stars allow identification of most of the binary stars in the sampleand, together with published uvbyβ photometry, Hipparcosparallaxes, Tycho-2 proper motions, and a few earlier radial velocities,complete the kinematic information for 14 139 stars. These high-qualityvelocity data are supplemented by effective temperatures andmetallicities newly derived from recent and/or revised calibrations. Theremaining stars either lack Hipparcos data or have fast rotation. Amajor effort has been devoted to the determination of new isochrone agesfor all stars for which this is possible. Particular attention has beengiven to a realistic treatment of statistical biases and errorestimates, as standard techniques tend to underestimate these effectsand introduce spurious features in the age distributions. Our ages agreewell with those by Edvardsson et al. (\cite{edv93}), despite severalastrophysical and computational improvements since then. We demonstrate,however, how strong observational and theoretical biases cause thedistribution of the observed ages to be very different from that of thetrue age distribution of the sample. Among the many basic relations ofthe Galactic disk that can be reinvestigated from the data presentedhere, we revisit the metallicity distribution of the G dwarfs and theage-metallicity, age-velocity, and metallicity-velocity relations of theSolar neighbourhood. Our first results confirm the lack of metal-poor Gdwarfs relative to closed-box model predictions (the ``G dwarfproblem''), the existence of radial metallicity gradients in the disk,the small change in mean metallicity of the thin disk since itsformation and the substantial scatter in metallicity at all ages, andthe continuing kinematic heating of the thin disk with an efficiencyconsistent with that expected for a combination of spiral arms and giantmolecular clouds. Distinct features in the distribution of the Vcomponent of the space motion are extended in age and metallicity,corresponding to the effects of stochastic spiral waves rather thanclassical moving groups, and may complicate the identification ofthick-disk stars from kinematic criteria. More advanced analyses of thisrich material will require careful simulations of the selection criteriafor the sample and the distribution of observational errors.Based on observations made with the Danish 1.5-m telescope at ESO, LaSilla, Chile, and with the Swiss 1-m telescope at Observatoire deHaute-Provence, France.Complete Tables 1 and 2 are only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/989
| Interstellar Extinction in the Direction of the Barnard 1 Dark Cloud in Perseus
Spectral and luminosity classes, absolute magnitudes, color excesses,interstellar extinctions and distances are determined for 98 stars downto 13 mag in the Barnard 1 dark cloud belonging to the Per OB2association. The classification of stars is based on theirphotoelectric photometry in the Vilnius seven-color photometric system.The extinction vs. distance diagram exhibits the presence of two dustlayers at 150 and 230 pc distances. The distance of the first cloud,which gives an extinction A_V of 0.3 mag, coincides with the distance ofthe Taurus dark cloud complex. The second cloud with much largerextinction is about at the same distance as the clouds in the directionof the nearby objects: reflection nebula NGC 1333 and open cluster IC348.
| Observations of Star-Forming Regions with the Midcourse Space Experiment
We have imaged seven nearby star-forming regions, the Rosette Nebula,the Orion Nebula, W3, the Pleiades, G300.2-16.8, S263, and G159.6-18.5,with the Spatial Infrared Imaging Telescope on the Midcourse SpaceExperiment (MSX) satellite at 18" resolution at 8.3, 12.1, 14.7, and21.3 μm. The large angular scale of the regions imaged (~7.2-50deg2) makes these data unique in terms of the combination ofsize and resolution. In addition to the star-forming regions, twocirrus-free fields (MSXBG 160 and MSXBG 161) and a field near the southGalactic pole (MSXBG 239) were also imaged. Point sources have beenextracted from each region, resulting in the identification over 500 newsources (i.e., no identified counterparts at other wavelengths), as wellas over 1300 with prior identifications. The extended emission from thestar-forming regions is described, and prominent structures areidentified, particularly in W3 and Orion. The Rosette Nebula isdiscussed in detail. The bulk of the mid-infrared emission is consistentwith that of photon-dominated regions, including the elephant trunkcomplex. The central clump, however, and a line of site toward thenorthern edge of the cavity show significantly redder colors than therest of the Rosette complex.
| Photometric Investigation of the MBM 12 Molecular Cloud Area in Aries. I. Photoelectric Photometry
The results of photoelectric photometry in the Vilnius seven-colorsystem are given for 152 stars down to 12.2 mag in the area of themolecular cloud MBM 12 and the dust clouds L1454 and L1457 in Aries. Theresults of photometric classification of stars are also given. Theinvestigation of interstellar extinction in the area is described in thenext paper.
| HIPPARCOS age-metallicity relation of the solar neighbourhood disc stars
We derive age-metallicity relations (AMRs) and orbital parameters forthe 1658 solar neighbourhood stars to which accurate distances aremeasured by the HIPPARCOS satellite. The sample stars comprise 1382 thindisc stars, 229 thick disc stars, and 47 halo stars according to theirorbital parameters. We find a considerable scatter for thin disc AMRalong the one-zone Galactic chemical evolution (GCE) model. Orbits andmetallicities of thin disc stars show now clear relation each other. Thescatter along the AMR exists even if the stars with the same orbits areselected. We examine simple extension of one-zone GCE models whichaccount for inhomogeneity in the effective yield and inhomogeneous starformation rate in the Galaxy. Both extensions of the one-zone GCE modelcannot account for the scatter in age - [Fe/H] - [Ca/Fe] relationsimultaneously. We conclude, therefore, that the scatter along the thindisc AMR is an essential feature in the formation and evolution of theGalaxy. The AMR for thick disc stars shows that the star formationterminated 8 Gyr ago in the thick disc. As already reported by Grattonet al. (\cite{Gratton_et.al.2000}) and Prochaska et al.(\cite{Prochaska_et.al.2000}), thick disc stars are more Ca-rich thanthin disc stars with the same [Fe/H]. We find that thick disc stars showa vertical abundance gradient. These three facts, the AMR, verticalgradient, and [Ca/Fe]-[Fe/H] relation, support monolithic collapseand/or accretion of satellite dwarf galaxies as likely thick discformation scenarios. 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/394/927
| Determination of highly precise proper motions for 32 HIPPARCOS stars from photographic plates.
Not Available
| High-precision positions and proper motions of 441 stars in the Pleiades astrometric standard region.
Not Available
| CCD photometry of a δ Scuti variable in an open cluster: V650 Tau in the Pleiades.
Time resolved CCD differential photometry was carried out for theδ Scuti variable V650 Tau on fourteen nights between November andDecember, 1993(total 3707 points of differential B magnitudes duringabout 81 hours observation). By applying the Fourier analysis to theobserved data, we have detected five frequencies(f_1_=377.7μHz,f_2_=197.3μHz, f_3_=292.8μHz, f_4_=333.0μHz, f_5_=214.1μHz).Among these, the amplitudes of two frequencies, f_1_ and f_2_, show somedifferences from the preliminary results of STEPHI network(Michel et al.1995). The comparison of observed frequency ratios and pulsationconstants with theoretical ones suggests that V650 Tau may pulsatesimultaneously in two dominant radial(F, 3H) and three nonradial modes.
| 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.
| Stroemgren photometry of F- and G-type stars brighter than V = 9.6. I. UVBY photometry
Within the framework of a large photometric observing program, designedto investigate the Galaxy's structure and evolution, Hβ photometryis being made for about 9000 stars. As a by-product, supplementary uvbyphotometry has been made. The results are presented in a cataloguecontaining 6924 uvby observations of 6190 stars, all south ofδ=+38deg. The overall internal rms errors of one observation(transformed to the standard system) of a program star in the interval6.5
| SPIDER : a program for computing the positions of fibers for multi-objects spectroscopy.
Not Available
| America's Last Pleiades Occultation
Not Available
| Determination of the Proper Motions for Stars in the Region of the Pleiades - Part One
Not Available
| Interstellar extinction in the direction of the Merope dark cloud in Pleiades
The dependence of interstellar extinction on distance in the directionof the dark cloud south of Merope is determined using photoelectricphotometry of 93 stars in the Vilnius photometric system. The cloudfront edge is detected at 120-130 pc from the sun, and the distance ofthe Pleiades cluster is found to be 127 pc. Mean extinction, A(V), inthe Merope cloud is of the order of 1.0 mag. There is no evidence ofextinction at distances exceeding the Merope cloud distance. Thevariable extinction method yields R = A(V)/E(B-V) = 3.6, while themaximum polarization wavelength method gives the value 3.4. SomePleiades stars are suspected to be unresolved binaries.
| Low Temperature Carbon Stars in the Vilnius Photometric System - Part Two
Not Available
| The Pleiades cluster. III - Polarization, reddening, and the unusual distribution of interstellar matter
A polarization survey of Pleiades cluster members and nonmembers hasbeen carried out together with a determination of interstellar reddeningfor cluster members. The ISM in front of and inside the cluster leads tovariable polarization and reddening across the cluster. The optical datacorrelate well with available radio and millimeter features. Twodistinct ISM concentrations are isolated: (1) a uniform foreground sheetin front of the whole cluster which is seen as constant reddening andpolarization in the eastern part of the cluster; and (2) additionalintracluster material, located mainly in the western part of thecluster.
| Lunar occultation summary. II
Results of a second series of 196 two-color photoelectric lunaroccultation observations made within the interval from May 1972 toDecember 1973 are reported. Each observation has been employed toestimate the minimum magnitude difference between the observed objectand possible undetected companions. The study contains the analyses of143 disappearances and 53 reappearances. Eighteen of these eventsmanifest some degree of multiplicity. Included in the study are 18occultation events for Pleiades members.
| Spectral classification and UBV H BET photometry.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977ApJ...213..105D&db_key=AST
| A spectroscopic investigation of the Pleiades.
Not Available
| Accurate positions of 502 stars in the region of the Pleiades
Not Available
| Catalog of Indidual Radial Velocities, 0h-12h, Measured by Astronomers of the Mount Wilson Observatory
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJS...19..387A&db_key=AST
| Star in the group of the Pleiades but not belonging to the physical system.
Not Available
| Photovisual magnitudes of the stars in the Pleiades.
Not Available
| The luminosities and parallaxes of five hundred stars.
Not Available
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Besorolás csoportokba:
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Pozíciós és asztrometriai adatok
| Csillagkép: | Bika |
| Rektaszcenzió: | 03h47m17.14s |
| Deklináció: | +23°43'36.3" |
| Vizuális fényesség: | 6.974 |
| Távolság: | 62.112 parszek |
| RA sajátmozgás: | -34.7 |
| Dec sajátmozgás: | -25.1 |
| B-T magnitude: | 7.595 |
| V-T magnitude: | 7.026 |
Katalógusok és elnevezések:
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INHABITED SKY
