Contents
Images
Upload your image
DSS Images Other Images
Related articles
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
| Statistics of spectroscopic sub-systems in visual multiple stars
A large sample of visual multiples of spectral types F5-M has beensurveyed for the presence of spectroscopic sub-systems. Some 4200 radialvelocities of 574 components were measured in 1994-2000 with thecorrelation radial velocity meter. A total of 46 new spectroscopicorbits were computed for this sample. Physical relations are establishedfor most of the visual systems and several optical components areidentified as well. The period distribution of sub-systems has a maximumat periods from 2 to 7 days, likely explained by a combination of tidaldissipation with triple-star dynamics. The fraction of spectroscopicsub-systems among the dwarf components of close visual binaries withknown orbits is similar to that of field dwarfs, from 11% to 18% percomponent. Sub-systems are more frequent among the components of widevisual binaries and among wide tertiary components to the known visualor spectroscopic binaries - 20% and 30%, respectively. In triple systemswith both outer (visual) and inner (spectroscopic) orbits known, we findan anti-correlation between the periods of inner sub-systems and theeccentricities of outer orbits which must be related to dynamicalstability constraints. Tables 1, 2, and 6 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/382/118
| ICCD Speckle Observations of Binary Stars. XXIII. Measurements during 1982-1997 from Six Telescopes, with 14 New Orbits
We present 2017 observations of 1286 binary stars, observed by means ofspeckle interferometry using six telescopes over a 15 year period from1982 April to 1997 June. These measurements constitute the 23dinstallment in CHARA's speckle program at 2 to 4 m class telescopes andinclude the second major collection of measurements from the MountWilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are alsopresented for 14 systems, seven of which have had no previouslypublished orbital analyses.
| Visual binary orbits and masses POST HIPPARCOS
The parallaxes from Hipparcos are an important ingredient to derive moreaccurate masses for known orbital binaries, but in order to exploit theparallaxes fully, the orbital elements have to be known to similarprecision. The present work gives improved orbital elements for some 205systems by combining the Hipparcos astrometry with existing ground-basedobservations. The new solutions avoid the linearity constraints andomissions in the Hipparcos Catalog by using the intermediate TransitData which can be combined with ground-based observations in arbitarilycomplex orbital models. The new orbital elements and parallaxes give newmass-sum values together with realistic total error-estimates. To getindividual masses at least for main-sequence systems, the mass-ratioshave been generally estimated from theoretical isochrones and observedmagnitude-differences. For some 25 short-period systems, however, trueastrometric mass-ratios have been determined through the observedorbital curvature in the 3-year Hipparcos observation interval. Thefinal result is an observed `mass-luminosity relation' which falls closeto theoretical expectation, but with `outliers' due to undetectedmultiplicity or to composition- and age-effects in the nonuniformnear-star sample. Based in part on observations collected with the ESAHipparcos astrometry satellite. Tables~ 1, 3, 4 and 6 are also availablein electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr~(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Mass determination of astrometric binaries with Hipparcos. III. New results for 28 systems
This paper is the third of a series devoted to the determination ofstellar masses from Hipparcos data. This is a continuation of Martin etal. (1997), who introduced the theory and assessed the performance ofthe method from simulated data, and of a second paper with the firstresults for 46 systems, ( te[Martin & Mignard 1998]{Mar98}). Theorbit file maintained by the CHARA group and new publications of orbitalelements made the processing of 70 additional candidate systemspossible, including 28 of the 145 systems already tested in the previouswork. Significant results were obtained on 22 systems, with relativeaccuracy better than 25% for the masses of 17 binaries. New estimatesare also given for 6 systems previously investigated, thanks to reliablevalues of the magnitude difference from the Hipparcos catalogue ( te[ESA1997]{ESA97}). New orbital elements are proposed for HIP 12623 (12Persei) from speckle/spectroscopic measurements. Results are discussedfor each system, alongside the mass-luminosity relation based onHipparcos magnitudes and distances.
| Mass determination of astrometric binaries with Hipparcos. II. Selection of candidates and results
In a previous paper (\cite{Mar97}) we have shown that for double starswith orbital periods smaller than about 25 years, it was possible todetermine from the Hipparcos data, the mass ratio B of the components orthe difference between the mass and intensity ratios, beta -B, providedthe orbital elements of the relative orbit are available. From anextensive literature search we have selected 145 potential systems, ofwhich 46 yielded eventually a satisfactory solution. For eight systemswith the largest separations, the peculiarities of the natural directionassociated to the Hipparcos observations, the 'hippacentre', have beenfully exploited to derive the mass ratio of the components without anyadditional assumption. For the remaining 38, the derivation of the massratio was possible only by taking the magnitude difference between thetwo components from other sources. The parallax determinedsimultaneously, is then used to produce the individual masses of thecomponents. The astrophysical relevance of the results is discussed andwhen possible (17 systems) the masses are compared to ground-basedvalues.
| Mesures d'etoiles doubles faites aux lunettes de 74 et 50 CM de l'Observatoire de la Cote d'Azur
We give 657 measurements of double stars, Table 1 by R. Gili with CCDcamera, Table 2 by P. Couteau with filar micrometer. Tables 1 and 2 areonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html.
| Interferometric observations of double stars in 1986-1990
A tabulation is presented for the measurements of double stars that havebeen conducted with the photometric phase-grating interferometer of theMt. Sanglok 1-m reflector. The tabulation encompasses the observationepoch, the position angle, the separation in arcsec, the magnitudedifference, formal errors in P.A. and separation, SAO number, andcoordinates for 2000.0.
| Binary-star measurements carried out at PIC DU Midi and at Nice
Data on 219 measurements of 103 close binaries observed with the 2mtelescope at Pic du Midi are presented. Also presented are data on 230measurements of 126 binaries observed with the 74 cm refractor of theNice Observatory.
| ICCD speckle observations of binary stars. V - Measurements during 1988-1989 from the Kitt Peak and the Cerro Tololo 4 M telescopes
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990AJ.....99..965M&db_key=AST
| Binary star measurements made at Pic-du-Midi
The 2-m Pic-du-Midi telescope has been used to obtain 130 visualmeasurements of 64 very close binaries. The measurements were made withan illuminated cross wire micrometer which provided magnificationfactors of 2500 to 5000. Data are presented in tabular form for suchmeasurements as total visual magnitude, angular position andseparations, and period.
| Interferometric Observations of Double Stars in 1985 and 1986
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1988A&AS...72..563T&db_key=AST
| The orbits of eleven binary stars
The orbits of HR 3880 = 19 Leo, ADS 7952, and Cou 1145 were computed.The previously known orbits of ADS 7662, ADS 10624, ADS 13777, and Cou542 were recalculated, and the orbits of Cou 79, ADS 9744, ADS 10092,and ADS 14893 were corrected to eliminate unacceptably largediscrepancies with recent interferometric observations. The dynamicparallaxes and masses are determined.
| ICCD speckle observations of binary stars. II - Measurements during 1982-1985 from the Kitt Peak 4 M telescope
This paper represents the continuation of a systematic program of binarystar speckle interferometry initiated at the 4 m telescope on Kitt Peakin late 1975. Between 1975 and 1981, the observations were obtained witha photographic speckle camera, the data from which were reduced byoptical analog methods. In mid-1982, a new speckle camera employing anintensified charge-coupled device as the detector continued the programand necessitated the development of new digital procedures for reducingand analyzing speckle data. The camera and the data-processingtechniques are described herein. This paper presents 2780 newmeasurements of 1012 binary and multiple star systems, including thefirst direct resolution of 64 systems, for the interval 1982 through1985.
| Spectral classification of weak-lined stars discovered photometrically
A random sample of 140 stars of the 800+ members in Olsen's (1984)sample of stars believed to be weak-lined has been observed andclassified independently of knowledge of the stars' photometriccharacteristics. It is found that 97 percent of the proposed weak-lineddwarfs are indeed such; the remainder are composites or normal, moreluminous stars. Deficiencies in the metallic-line types are comparedwith (Fe/H) values and metallic strength indices. These comparisons showthat a metal deficiency of at least a factor of two is needed before thespectra look weak-lined.
| Interferometer observations of double stars. II
Position angles and separations of 83 visual binaries have been measuredwith a photoelectric phase-grating interferometer on a 1-m reflector.Twenty pairs deviate significantly from the ephemerides; nine starsremain unresolved. The magnitude limit of the interferometer iscalculated from the measured seeing and found to agree with the actuallimit of about nine magnitudes.
| The orbital elements of 43 visual binary stars
The orbital elements of 43 visual binaries (29 new, 14 revised) aregiven. The measures, the O-C residuals, the dynamical parallaxes, andthe ephemeris for the next 10 or 20 years are given for each pair.
| Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.
| Measurements of binary stars made at Nice
Results are presented for 753 measurements of 267 binary stars that weremade with the 50- and 74-cm refractors at Nice Observatory. Coordinatesfor the equinox of 1950 are provided, along with apparent magnitudes,spectral types, and probable periods. It is noted that three-quarters ofthese systems are recently discovered close binaries.
| Positions moyennes et mouvements propres de 355 etoiles DU GC de la zone de declinaison +33 +36.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...26..219M&db_key=AST
| The masses of stars above the main sequence.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969AJ.....74..689S&db_key=AST
| Mesures d'étoiles doubles faites au 0,38 m de l'Observatoire de Paris.
Not Available
| Micrometer Measures of Double Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959ApJS....4...45V&db_key=AST
| Double star observations at Lick Observatory
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954AJ.....59..388M&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Hercules |
| Right ascension: | 17h32m34.11s |
| Declination: | +34°44'47.6" |
| Apparent magnitude: | 7.979 |
| Distance: | 59.488 parsecs |
| Proper motion RA: | 32.7 |
| Proper motion Dec: | 10.8 |
| B-T magnitude: | 8.611 |
| V-T magnitude: | 8.032 |
Catalogs and designations:
|
INHABITED SKY
