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Photoelectric radial velocities, Paper XVI 625 ninth-magnitude K0 stars in the six southern Clube Selected Areas
Paper XIII of this series presented radial velocities for 406 stars incertain of the Clube Selected Areas, a set of areas systematicallyarranged in Galactic coordinates. We now complete the survey byproviding the radial velocities, mostly obtained at the EuropeanSouthern Observatory (ESO), of 625 stars in the six southernmost Areas.Each star has been measured at least twice; the mean velocities havestandard errors typically of 0.2-0.3 km s-1. Additionalobservations made from Haute-Provence of many of the stars that areobservable from there have helped to identify, and in some instances tocharacterize, the ~70 spectroscopic binaries discovered in thisprogramme. The final results of the programme, complementing those givenin table 3 of Paper XIII, are summarized in Table 12, which presents themean velocities and velocity dispersions in the six southern Areas. Itis noted that the difference between Paper XIII and this one as regardsthe provenance of the radial velocities has led to a small difference inzero-points, which is discussed in Section 3 and needs to be taken intoaccount in any analysis of the combined data.
| 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
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| A large, complete, volume-limited sample of G-type dwarfs. I. Completion of Stroemgren UVBY photometry
Four-colour photometry of potential dwarf stars of types G0 to K2,selected from the Michigan Spectral Catalogues (Vol. 1-3), has beencarried out. The results are presented in a catalogue containing 4247uvby observations of 3900 stars, all south of δ = -26deg. Theoverall internal rms errors of one observation (transformed to thestandard system) of a program star in the interval 8.5 < V < 10.5are 0.0044, 0.0021, 0.0039, and 0.0059, respectively, in V, b-y, m_1_ ,and c_1_. The purpose of the catalogue, combined with earliercatalogues, is to allow selection of a large, complete, volume-limitedsample of G- and K-type dwarfs, investigate their metallicitydistribution, and compare it to predictions of various models ofgalactic chemical evolution. Future papers in this series will discussthese subjects.
| A Survey of Southern Be Stars. II. Photometric data
Not Available
| Spectroscopic parameters of early type stars. I. Equivalent widths ofhydrogen lines.
Not Available
| Multicolor Photometry of Stellar Aggregates
We have made multicolor photometric observations over the range ofwavelength from 0.36 microns in the ultraviolet to 5.0 microns in theinfrared, on 1063 stars in the regions of h and x Persei, Pleiades,Hyades, Orion, Praesepe M 67, Scorpio-Centaurus, Coma Berenices and UrsaMajor stellar aggregates. Standard relations between V-R and the othercolors are obtained by using the UBVRI photometry. These observationsalso have been used to derive photometric distances. The range indistance covered is over a factor of 100, from nearly 22 parsecs (UrsaMajor-nucleus) to nearly 2300 parsecs (double cluster in Perseus). Thesame photometric results arc also used to define a zero-age mainsequence for visual absolute magnitudes. The range in V-R is from -0.15mag. to +1.00 mag. and the range in absolute magnitude is from,approximately, -4.0 to +7.43.
| Rotational velocities of southern B stars (1967).
Not Available
| BVRI Photoelectric Photometry for 275 Stars located between -25° y -50° Fotometría Fotoeléctrica en BVRI para 275 estrellas comprendidas en su mayoría entre -25° y -50°
BYRI photometry in Johnson's system was done for 275 stars the mayority ofwhich are comprised between -25° and -50°. Due to systematicvariations in V magnitude in R. A. of the order of 0.2 magnitude it wasdecided to use in the present work V magnitudes of the Catalogue of theRoyal Observatory, Cape of Good Hope, South Africa. The colours presentedhere, should permit to have an homogeneous R and I Systems of photometryfor both the Northern and Southern sky, complete to the fifth magnitude, anup to -50° in declination
| Photometric Magnitudes and Colours for Bright Southern Stars (Sixth List)
Not Available
| A Survey of Southern Be Stars
Not Available
| Emissions-B-Sterne und galaktische Struktur. Mit 6 Textabbildungen
Not Available
| Die galaktischen Emissions-B-Sterne : (Spectralklassifikation, Photometrie, Entwicklung und Verteilung in der Milchstraszenebene)
Not Available
| Catalogue of stellar spectra classified in the Morgan-Keenan system
Not Available
| Photometric Data for Stars in the Equatorial Zone (Seventh List)
Not Available
| Photometric and spectroscopic data for southern OB stars (1963).
Not Available
| Discovery and statistics of Be stars. Preliminary results.
Not Available
| The Radiation Field and Theoretical Balmer Decrements of the Stars, III
Abstract image available at:http://adsabs.harvard.edu/abs/1961PASJ...13..335K
| Early-type stars with extended atmospheres.
Not Available
| Spectral types of bright southern stars
Not Available
| Bright Variables Stars in the Southern Hemisphere
Not Available
| The luminosities and parallaxes of 350 stars of spectral type B
Not Available
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Miembro de los siguientes grupos:
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Datos observacionales y astrométricos
| Constelación: | Hidra macho |
| Ascensión Recta: | 00h51m24.65s |
| Declinación: | -78°38'38.5" |
| Magnitud Aparente: | 9.925 |
| Movimiento Propio en Ascensión Recta: | 173.4 |
| Movimiento Propio en Declinación: | -136 |
| B-T magnitude: | 11.093 |
| V-T magnitude: | 10.022 |
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INHABITED SKY
