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
|
Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
|
A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars
Among the 9110 stars in The Bright Star Catalogue, there are 225eclipsing or ellipsoidal variables. A search has been made for these incatalogues of spectroscopic binaries, visual double or multiple stars,speckle interferometry, occulation binaries, and galatic clusters. Themajority of the photometric binaries are also members of groups ofhigher multiplicity. The variables are in systems ranging from one to 91stars, five on the average. 199 are either spectroscopic binaries (SB)or stars with variable radial velocity, with orbital periods known for160. Photometric periods are lacking for 48 while SB periods areavailable for 23 of these. Observers with photoelectric equipment areencouraged to plan observations to test if the SB periods are consistentwith photometric data. Observers are likewise encouraged to examinethose stars for which the photometric and SB periods appear to beinconsistent. Parallaxes are available for 86 of the stars, 41 of themindicating distances nearer than 50 parsecs.
|
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.
|
Predicting the Secondary Minima Depths and Spectra of the Main Components for the Dm-Type Eclipsing Variable Stars
Not Available
|
Speckle observations of visual and spectroscopic binaries. IV
This is the fourth paper of this series giving results of speckleobservations for 22 visual and 161 spectroscopic binaries. Theobservation was carried out by using the 212 cm telescope of San PedroMartir Observatory in Mexico on 7 nights from July 20 to July 26, 1991.We obtained fringes in power spectra of 19 visual and 11 spectroscopicbinaries (6 newly resolved ones) with angular separation larger than0.06 arcsec. We introduced a new ICCD TV camera in this observation, andwere able to achieve the diffraction-limit resolution of the 212 cmtelescope.
|
Speckle observations of visual and spectroscopic binaries. III
This is the third paper of this series giving results of speckleobservations carried out for seven visual and 119 spectroscopic binariesat seven nights from May 20 to May 27, 1989, and for 30 visual and 272spectroscopic binaries at 12 nights from June 11 to June 15, and fromAugust 28 to September 3, 1990, using the 212-cm telescope at San PedroMartir Observatory in Mexico. Fringes in the lower spectrum of 31 visualand spectroscopic binaries with angular separation larger than 21 arcsecare obtained. Additionally to two spectroscopic binaries, HD41116 andHD206901, named in the second paper of this series, six spectroscopicbinaries are found each of which has the third component starsurrounding two stars of spectroscopic binary having periodic variationof radial velocity.
|
Close binaries observed polarimetrically
Not Available
|
Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
|
On the (B-V) colors of the bright stars
The possible causes of the dispersion of (B-V) colors of nearby stars inthe Bright Star Catalog are investigated. The distribution of (B-V)colors is presented for the entire range of spectral classes.Explanations for the dispersion in terms of a nonuniform distribution ofinterstellar absorbing material and a variability of metallicity areaddressed. A new statistical model for reddening by interstellar dustclouds is developed. It is concluded that extinction by nonuniforminterstellar matter is an important contribution to the reddening ofnearby stars, and that a part of the dispersion of (B-V) colors of Kand, possibly, M giants may be due to some unidentified variableproperty of those stars.
|
Durchmusterung offener Sternhaufen nach CP2-Sternen
Not Available
|
An Einstein Observatory X-ray survey of main-sequence stars with shallow convection zones
The results of an X-ray survey of bright late A and early F stars on themain B-V sequence between 0.1 and 0.5 are presented. All the stars wereobserved with the Einstein Observatory for a period of at least 500seconds. The survey results show significantly larger X-ray luminositiesfor the sample binaries than for the single stars. It is suggested thatthe difference is due to the presence of multiple X-ray sources inbinaries. It is shown that the X-ray luminosities for single starsincrease rapidly with increasing color, and that the relation Lx/Lbol isequal to about 10 to the -7th does not hold for A stars. No correlationwas found between X-ray luminosity and projected equatorial rotationvelocity. It is argued on the basis of the observations that X-rayemission in the sample stars originated from coronae. The availableobservational evidence supporting this view is discussed.
|
Stromgren photometry of open clusters. I - NGC 6281, NGC 6405
Stromgren indices for A-type and B-type stars in the southern openclusters, NGC 6281 and NGC 6405, are presented. Their membership isdiscussed and the reddening of the clusters is estimated. It is shownthat shifting of the main sequence to the standard relation of Crawford(1975, 1978, 1979) yields a reddening of E(b-y) = 0.120 for NGC 6281 anda reddening of E(b-y) = 0.110 for NGC 6405. The occurrence of a CP1(Am)and a Delta-Sct star in NGC 6405 is considered. The results of theStromgen photometry are given in tables.
|
Metallicities and Distances of Galactic Clusters as Determined from UBV Data - Part Three - Ages and Abundance Gradients of Open Clusters
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985A&A...147...47C&db_key=AST
|
Metallicities and distances of galactic clusters as determined from UBV-data. II - The metallicities and distances of 38 open clusters. III - Ages and abundance gradients of open clusters
After presenting a novel method for the simultaneous calculation of UVexcess and reddening in open clusters, the former is transformed into anFe/H abundance ratio value on the basis of the relation due to Cameron(1985), and the reddening is used to determine the distances of theclusters, incorporating a ratio of total-to-selective absorption that isboth a function of interstellar extinction and dependent on spectraltype. Metallicities and distances for 38 open clusters are therebyobtained and used to estimate the variation of metal abundance along thegalactic disk. The ages of the clusters are determined using the turnoffpoint method in the H-R diagram, and noted to cover a span of 5.1billion years. No firm relationship between cluster ages and theirmetallicity can be deduced; it is instead shown that, at a given age,there is a metallicity spread of up to + or - 0.3 dex.
|
The period distribution of unevolved close binary systems
Period distributions have been examined for various spectral types ofabout 600 (eclipsing and spectroscopic) close binaries, which are likelyto be substantially unevolved. The comparison with the previouscorresponding analyses of extensive (but heterogeneous) binary samplesallows a clarification of the extent of the evolutionary andobservational selection effects. Remarkably, this analysis reveals agreat deficiency of short period binaries (with periods corresponding tocase A mass transfer) in the whole spectral range. For the late spectraltypes, this result may be connected with postformation angular momentumloss caused by stellar wind magnetic braking; at least for the late Band A spectral range, a ready interpretation of this finding is thatclose binaries of corresponding periods and spectral types are rarelyformed.
|
Photoelectric search for CP2-stars in open clusters. V - NGC 6281, NGC 6405, IC 4665
130 stars in the medium age clusters NGC 6281, NGC 6405, and IC 4665were observed by photoelectric photometry in the Delta a-system(Maitzen, 1976) in order to detect CP2-peculiarity by the presence ofthe lambda 5200 depression feature. No CP2-star was found in IC 4665,one in NGC 6281, and 3 in NGC 6405. Star No. 77 of NGC 6405 exhibits thestrongest lambda 5200 depression ever measured by this type ofphotometry. The (very small) reddening correction of the a-values isdiscussed and found to agree well with previous papers of this series.
|
U,B,V photometry of the X-ray binary HD 153919 = 4U 1700-37
Photoelectric UBV photometry of HD 153919 was performed at the SidingSpring Observatory of the Australian National University duringMarch-June 1980. The light curves show a local minimum approximataely0.04 m deep at phases phi = 0.55-0.7, evidently due to occultation ofthe O6f star by gas streams and the accretion structure around therelativistic object. VB pulsations of 0.012-0.007 m amplitude and 85-94min period at phi = 0.5-0.6 are suspected, in accordance withKruszewski's (1978) finding that the optical pulsation period is growingshorter.
|
Variability of the emission-line spectra and optical continua of Seyfert galaxies. I
H-beta and O III forbidden line 4959,5007 A line strengths obtained fromnew observations of 27 broad line-emitting galaxies and six narrowline-emitting galaxies are compared with earlier measurements. It isfound that about 80% of broad line-emitting galaxies show significantchanges in their optical spectra, on time scales of less than about fiveyears. An analysis of changes in O II forbidden line/H-beta ratio for 24broad line-emitting galaxies shows that (1) changes in the H-beta fluxare correlated with changes in the optical continuum, providing evidencefor energy input into the line-emitting region by photoionization, and(2) in a number of galaxies, the structure of the broad emission linesin complex, with detailed line structure changes on time scales shorterthan about two months.
|
Close binary systems before and after mass transfer. III - Spectroscopic binaries
A method is presented, for the computation of absolute dimensions fromspectroscopic data on binary systems, which has been adapted for usewith the 7th Catalogue of Batten et al. (1978) and takes into accountseveral results of close binary evolution, with emphasis on the phase ofslow mass transfer during a case B mass transfer. Among the unevolvedsystems, the mass transfer case B is found to be the most abundant typeof interaction. In the set of evolving systems, a subset of 18interacting systems was found with mass ratio near unity, the first starbeing the mass loser as well as the brightest.
|
65th Name-List of Variable Stars
Not Available
|
List of Estimated Angular Separations of Spectroscopic Binaries
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1981A&AS...44...47H&db_key=AST
|
Seventh catalogue of the orbital elements of spectroscopic binary systems.
Not Available
|
Four colour photometric observations of the X-ray binary HD 153919 /3U 1700-37/
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977A&A....54..543H&db_key=AST
|
Photometry of stars near 3U 1700-37= HD 153919 and 3U 0900-40=HD 77581.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976AJ.....81..339B&db_key=AST
|
The open cluster NGC 6281
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974PASP...86..284F&db_key=AST
|
Régions H II de l'hémisphère austral
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970A&AS....3....1G&db_key=AST
|
The Southern spectroscopic binaries HD 16589, 24202, 15390 and 197649.
Not Available
|
The Wolf-Rayet stars.
Not Available
|
INHABITED SKY
