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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.
| Multiplicity among solar-type stars. III. Statistical properties of the F7-K binaries with periods up to 10 years
Two CORAVEL radial velocity surveys - one among stars in the solarneighbourhood, the other in the Pleiades and in Praesepe - are merged toderive the statistical properties of main-sequence binaries withspectral types F7 to K and with periods up to 10 years. A sample of 89spectroscopic orbits was finally obtained. Among them, 52 relate to afree-of-bias selection of 405 stars (240 field stars and 165 clusterstars). The statistics corrected for selection effects yield thefollowing results: (1) No discrepancy is found between the binariesamong field stars and the binaries in open cluster. The distributions ofmass ratios, of periods, the period-eccentricity diagram and the binaryfrequencies are all within the same error intervals. (2) Thedistribution of mass ratios presents two maxima: a broad peak from q ~0.2 to q ~ 0.7, and a sharp peak for q > 0.8 (twins). Both arepresent among the early-type as well as among the late-type part of thesample, indicating a scale-free formation process. The peak for q >0.8 gradually decreases when long-period binaries are considered.Whatever their periods, the twins have eccentricities significantlylower than the other binaries, confirming a difference in the formationprocesses. Twins could be generated by in situ formation followed byaccretion from a gaseous envelope, whereas binaries with intermediatemass ratios could be formed at wide separations, but they are madecloser by migration led by interactions with a circumbinary disk. (3)The frequency of binaries with P<10 years is about 14%. (4) About0.3% of binaries are expected to appear as false positives in a planetsearch. Therefore, the frequency of planetary systems among stars ispresently 7+4-2%. The extension of thedistribution of mass ratios in the planetary range would result in avery sharp and very high peak, well separated from the binary stars withlow mass ratios. Based on photoelectric radial-velocity measurementscollected at Haute-Provence observatory and on observations made withthe ESA Hipparcos astrometry satellite.
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| 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.
| CA II H and K measurements made at Mount Wilson Observatory, 1966-1983
Summaries are presented of the photoelectric measurements of stellar CaII H and K line intensity made at Mount Wilson Observatory during theyears 1966-1983. These results are derived from 65,263 individualobservations of 1296 stars. For each star, for each observing season,the maximum, minimum, mean, and variation of the instrumental H and Kindex 'S' are given, as well as a measurement of the accuracy ofobservation. A total of 3110 seasonal summaries are reported. Factorswhich affect the ability to detect stellar activity variations andaccurately measure their amplitudes, such as the accuracy of the H and Kmeasurements and scattered light contamination, are discussed. Relationsare given which facilitate intercomparison of 'S' values with residualintensities derived from ordinary spectrophotometry, and for convertingmeasurements to absolute fluxes.
| Multiplicity among solar type stars in the solar neighbourhood. I - CORAVEL radial velocity observations of 291 stars
Results obtained on stellar radial velocity of 291 stars of spectraltypes FO to G9, measured with CORAVEL spectrometers at theHaute-Provence and la Silla Observatories, are discussed. The paperdescribes the observational procedure, reduction technique, andvelocity-data calibration and presents a list of individualradial-velocity measurements. Few histograms describing the survey arealso presented.
| Multiplicity among solar-type stars in the solar neighbourhood. II - Distribution of the orbital elements in an unbiased sample
An unbiased sample of 164 primary G-dwarf stars in the solarneighborhood are studied with the aid of 4200 radial velocities obtainedduring almost 13 yrs. Several present-day distributions of the orbitalelements are derived. For systems with M(2)/M(1) above 0.1 in the nearbyG-dwarf sample, the following results are obtained: (1) The orbitalperiod distribution is unimodal and can be approximated by aGaussian-type relation with a median period of 180 yrs. (2) The shortbinaries are circularized up to orbital periods of about 11 d due to thetidal evolution effects - a result compatible with the mean age of theGalactic disk. (3) The tight binaries not affected by tidal effects (inthe range between 11 and 1000 d) may reflect the initial binaryformation process, and they have a mean eccentricity of 0.31 +/-0.04.For systems with M(2)/M(1) not greater than 0.1, the proportion of browndwarf companions among the IAU velocity standards is estimated at 10percent of the primaries, a value in good agreement with that found inthe G-dwarf sample.
| BVRI photometry of the Gliese Catalogue stars
Photoelectri BVRI photometry on the Cousins (Kron-Cape) system has beenobtained for many of the southern faint stars in the Gliese Catalog(1969). This extends the work of Cousins (1980) and provides a uniformset of data for the nearby stars. Several red dwarfs are noted, whichwere used to define the red end of the Cousins system.
| Chromospheric activity in evolved stars - The rotation-activity connection and the binary-single dichotomy
A tabulation of measured values of the Ca II H and K (S) index aretransformed to the original Mount Wilson definition of the index. Thetabulation includes main-sequence, evolved, single, and tidally coupled(RS CVn) binary stars. The (S) indices are analyzed against Wilson's(1976) I(HK) intensity estimates, showing that Wilson's estimates areonly a two-state indicator. Ca II H and K fluxes are computed andcalibrated with published values of rotation periods. It is found thatthe single and binary stars are consistent with a single relationshipbetween rotation and Ca II excess emission flux.
| The chromospheric age dependence of the birthrate, composition, motions, and rotation of late F and G dwarfs within 25 parsecs of the sun
The chromospheric ages of 115 late F and G dwarfs within 25 parsecs ofthe sun are calculated. Rotational velocities are plotted againstchromospheric age to reveal the rotational spin-down trajectories ofsolar-type stars of various masses. Also, plots of metal abundance andpeculiar velocity versus chromospheric age are used to determine trendswith age.
| G. P. Kuiper's spectral classifications of proper-motion stars
Spectral classifications are listed for over 3200 stars, mainly of largeproper motion, observed and classified by Kuiper during the years1937-1944 at the Yerkes and McDonald Observatories. While Kuiper himselfpublished many of his types, and while improved classifications are nowavailable for many of these stars, much of value remains. For many ofthe objects, no other spectral data exist.
| A survey of chromospheric emission and rotation among solar-type stars in the solar neighborhood
A spectroscopic survey of Ca II and H and K emission among late-typedwarfs is analyzed in order to identify solar neighborhood stars with(B-V) greater than 0.50 and less than 1.00. The observations were usedto calculate RHK, the fraction of the bolometric luminosityof a star which appears as HK emission. The angular velocities of thestars relative to the sun (Omega/Omega solar radius) were calculatedbased on a calibration of RHK with the Rossby number. Therelationship between age and the rotational properties of the stars wasalso analyzed in detail. It is shown that for stars of a givenRHK, age RHK increases slightly with increasing(B-V). The activity-age relation (RHK varies as exp -1/2) wasfound to be independent of mass for the late-type dwarfs. Therotation-age relation was also independent of mass, and the rotationrate of the sun was found to be normal for a star of its mass and age.It is suggested that the age dependencies of chromospheric activity arealso unrelated to mass and angular momentum loss may be considered aself-regulating mechanism which is not related to the details of stellarstructure such as the convective zone depth.
| Results of the Herstmonceux parallax programme. III
Herstmonceux parallaxes measured with the 26-in. refractor for 28 starsare presented. Parameters examined include photometric V and Bmagnitudes to 0.01 mag or approximate visual and photographic magnitudesto 0.1 mag; the approximate effective photographic magnitude; theparallax weights of the right ascension and combined solutions; therelative parallax solutions and their standard errors; and the adoptedparallax, absolute magnitude, and the positive and negative rangecorresponding to the standard error of the relative parallax. A weakcorrelation appears to exist between the relative parallax solutions andright ascension. Though the phase is similar to that obtained by Thomas(1973), the variation is much smaller. Both the phase and the amplitudeof the relative parallax solutions are approximately the same as thoseobtained by Lippincott (1971).
| Predicted infrared brightness of stars within 25 parsecs of the sun
Procedures are given for transforming selected optical data intoinfrared flux densities or irradiances. The results provide R, T(eff)blackbody approximations for about 2000 of the stars in Woolley et al.'sCatalog of Stars (1970) within 25 pc of the sun, and additional whitedwarfs, with infrared flux densities predicted for them at ninewavelengths from 2.2 to 101 microns including the Infrared AstronomySatellite bands.
| Meridian observations made with the Carlsberg Automatic Meridian Circle at Brorfelde (Copenhagen University Observatory) 1981-1982
The 7-inch transit circle instrument with which the present position andmagnitude catalog for 1577 stars with visual magnitudes greater than11.0 was obtained had been equipped with a photoelectric moving slitmicrometer and a minicomputer to control the entire observationalprocess. Positions are reduced relative to the FK4 system for each nightover the whole meridian rather than the usual narrow zones. Thepositions of the FK4 stars used in the least squares solution are alsogiven in the catalog.
| DDO Observations of Southern Stars
Not Available
| VRI photometry of nearby stars.
Not Available
| Three-dimensional motion of dwarf stars and RR Lyrae variables
A collection of 220 high-velocity dwarfs, 532 low-velocity dwarfs, and114 RR Lyrae variables is given in tables with calculations ofkinematical quantities in a three-dimensional model of galactic space. Ametal indicator, Delta-S, for RR Lyrae variables is transformed into theultraviolet excess, delta (0.6), which is utilized for a statisticalstudy of kinematics under the same metallicity classification. It isfound that the primordial Galaxy contracted by a factor of at least 20in the radial direction as compared to at least 50 in the Z direction.
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Membre dels grups següents:
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Dades d'Observació i Astrometria
| Constel·lació: | Aquarius |
| Ascensió Recta: | 20h59m32.80s |
| Declinació: | +01°03'56.4" |
| Magnitud Aparent: | 8.625 |
| Distancia: | 47.664 parsecs |
| Moviment propi RA: | 226.9 |
| Moviment propi Dec: | 105.6 |
| B-T magnitude: | 9.445 |
| V-T magnitude: | 8.693 |
Catàlegs i designacions:
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