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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
| CCD measurements of visual double stars from the German-Spanish Astronomical Center at Calar Alto
342 CCD measurements of relative positions and magnitude differences for145 visual double stars are presented. Observations were carried out atthe 1.23m telescope of the German-Spanish Astronomical Center at CalarAlto (Spain), all of them in V and R photometric bands.
| CCD astrometry and instrumental Delta V photometry of visual double stars. V. Differential measurements of pairs with angular separations 1arcsec to 4arcsec
We present angular separations, position angles and Delta V instrumentalmagnitude differences of 83 visual double stars with angular separationsaround two arcseconds. Our observations were made by means of a CCDdetector attached to the Kryonerion 1.2 m telescope. 12 of them arecommon proper motion stars and their components should therefore bestars of common origin. Based on observations made at KryonerionObservatory, Greece. Table 2 only available at the CDS via anonymous ftpto cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html}
| A photometric study of wide visual double stars with significant relative proper motion
Photometric observations and uvby H-beta indices of 142 wide visualdouble stars are presented. Calibrations of the indices are used toderive MK class, color excess, absolute magnitude, effectivetemperature, and distance. The results are used to check candidatesdouble stars for the Hipparcos mission for opticity.
| Comparison of proper motions obtained by means of rectilinear trajectories of optical double stars with those given by the SAO catalog
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1979A&A....71...55D&db_key=AST
| Photographic measures of double stars. II
Measures are presented for 302 double stars photographed on 657 plateswith the 36-in. Lick refractor in the period between 1945 and 1962. Thedata provided include the observing epochs, the rectangular coordinatesof the secondary components with reference to the respective primaries,the mean errors of a single measurement, the computed mean errors, thedouble-star separations, and the position angles both for the observingepoch and reduced to the equator of 2000. An additional 561 unmeasuredplates of acceptable quality obtained between 1948 and 1960 are listed.
| Photographic measures of doubles stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1964AJ.....69..762G&db_key=AST
| Mouvement relatif linéaire d'étoiles doubles
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | פגסוס |
| התרוממות ימנית: | 22h32m34.71s |
| סירוב: | +07°24'56.6" |
| גודל גלוי: | 9.484 |
| תנועה נכונה: | 35 |
| תנועה נכונה: | 15.8 |
| B-T magnitude: | 9.929 |
| V-T magnitude: | 9.521 |
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