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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
| Binary Star Orbits. II. Preliminary First Orbits for 117 Systems
Orbital elements are presented for 117 binary systems with no previousorbit calculation. For nearly all of these systems, these elements mustbe regarded as preliminary, but the ephemerides presented here should berelatively accurate over the next several decades. Further, the analysisof these systems should highlight the need for their continuedobservation by dedicated programs to improve the veracity of theseelements.
| Micrometer Measures of Double Stars
Micrometer measures of 795 double stars made with the 26 inch (0.66 m)refractor of the US Naval Observatory from 1984 to 1990 are presented.
| Observations of Double Stars. XVIII.
Micrometer observations of 1350 pairs in 1995-1997 are listed.
| 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
| Observations of double stars and new pairs. XIV
Results of a continuing survey of visual double stars are presented,including 4880 measurements made from February 1987 to November 1989.The positions in WDS format and Durchmusterung numbers are given for 194pairs first reported here. Micrometer measurements of 1142 doubles madewith the Swarthmore 61 cm refractor are presented. Magnitudes areestimated for some of the objects. Plate measurements, plateorientations, position angles, number of nights, and measured exposuresare given. Visual observations of 342 pairs obtained in May 1989 atCerro Tololo, mostly with the 1.0 m reflector, are reported.
| Micrometer Observations of Double Stars and New Pairs - Part Ten
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980ApJS...44..111H&db_key=AST
| Double star observations made with the 28-inch refractor 1963-1970.
Not Available
| Mesures d'etoiles doubles a Meudon (3eme et derniere serie).
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...23..205M&db_key=AST
| Photoelectric observations of lunar occultations.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970A&A.....5..328D&db_key=AST
| Mikrometermessungen von Doppelsternen. VI.
Not Available
| Mesures d'étoiles doubles faites au rĝfraceur de 38 cm de l'Observatoire de Nice
Not Available
| Mesures photométriques d'Etoiles Doubles au télescope de 0. 80 m. de l'Observatoire de Hauteprovence
Not Available
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Pozíciós és asztrometriai adatok
| Csillagkép: | Oroszlán |
| Rektaszcenzió: | 10h29m11.37s |
| Deklináció: | +10°09'20.0" |
| Vizuális fényesség: | 7.176 |
| RA sajátmozgás: | -3 |
| Dec sajátmozgás: | -29.8 |
| B-T magnitude: | 7.83 |
| V-T magnitude: | 7.23 |
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