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Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
The availability of the Hipparcos Catalogue has triggered many kinematicand dynamical studies of the solar neighbourhood. Nevertheless, thosestudies generally lacked the third component of the space velocities,i.e., the radial velocities. This work presents the kinematic analysisof 5952 K and 739 M giants in the solar neighbourhood which includes forthe first time radial velocity data from a large survey performed withthe CORAVEL spectrovelocimeter. It also uses proper motions from theTycho-2 catalogue, which are expected to be more accurate than theHipparcos ones. An important by-product of this study is the observedfraction of only 5.7% of spectroscopic binaries among M giants ascompared to 13.7% for K giants. After excluding the binaries for whichno center-of-mass velocity could be estimated, 5311 K and 719 M giantsremain in the final sample. The UV-plane constructed from these datafor the stars with precise parallaxes (σπ/π≤20%) reveals a rich small-scale structure, with several clumpscorresponding to the Hercules stream, the Sirius moving group, and theHyades and Pleiades superclusters. A maximum-likelihood method, based ona Bayesian approach, has been applied to the data, in order to make fulluse of all the available stars (not only those with precise parallaxes)and to derive the kinematic properties of these subgroups. Isochrones inthe Hertzsprung-Russell diagram reveal a very wide range of ages forstars belonging to these groups. These groups are most probably relatedto the dynamical perturbation by transient spiral waves (as recentlymodelled by De Simone et al. \cite{Simone2004}) rather than to clusterremnants. A possible explanation for the presence of younggroup/clusters in the same area of the UV-plane is that they have beenput there by the spiral wave associated with their formation, while thekinematics of the older stars of our sample has also been disturbed bythe same wave. The emerging picture is thus one of dynamical streamspervading the solar neighbourhood and travelling in the Galaxy withsimilar space velocities. The term dynamical stream is more appropriatethan the traditional term supercluster since it involves stars ofdifferent ages, not born at the same place nor at the same time. Theposition of those streams in the UV-plane is responsible for the vertexdeviation of 16.2o ± 5.6o for the wholesample. Our study suggests that the vertex deviation for youngerpopulations could have the same dynamical origin. The underlyingvelocity ellipsoid, extracted by the maximum-likelihood method afterremoval of the streams, is not centered on the value commonly acceptedfor the radial antisolar motion: it is centered on < U > =-2.78±1.07 km s-1. However, the full data set(including the various streams) does yield the usual value for theradial solar motion, when properly accounting for the biases inherent tothis kind of analysis (namely, < U > = -10.25±0.15 kms-1). This discrepancy clearly raises the essential questionof how to derive the solar motion in the presence of dynamicalperturbations altering the kinematics of the solar neighbourhood: doesthere exist in the solar neighbourhood a subset of stars having no netradial motion which can be used as a reference against which to measurethe solar motion?Based on observations performed at the Swiss 1m-telescope at OHP,France, and on data from the ESA Hipparcos astrometry satellite.Full Table \ref{taba1} is 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/430/165}
| Radial Velocities for 889 Late-Type Stars
We report radial velocities for 844 FGKM-type main-sequence and subgiantstars and 45 K giants, most of which had either low-precision velocitymeasurements or none at all. These velocities differ from the standardstars of Udry et al. by 0.035 km s-1 (rms) for the 26 FGKstandard stars in common. The zero point of our velocities differs fromthat of Udry et al.: =+0.053km s-1. Thus, these new velocities agree with the best knownstandard stars both in precision and zero point, to well within 0.1 kms-1. Nonetheless, both these velocities and the standardssuffer from three sources of systematic error, namely, convectiveblueshift, gravitational redshift, and spectral type mismatch of thereference spectrum. These systematic errors are here forced to be zerofor G2 V stars by using the Sun as reference, with Vesta and day sky asproxies. But for spectral types departing from solar, the systematicerrors reach 0.3 km s-1 in the F and K stars and 0.4 kms-1 in M dwarfs. Multiple spectra were obtained for all 889stars during 4 years, and 782 of them exhibit velocity scatter less than0.1 km s-1. These stars may serve as radial velocitystandards if they remain constant in velocity. We found 11 newspectroscopic binaries and report orbital parameters for them. Based onobservations obtained at the W. M. Keck Observatory, which is operatedjointly by the University of California and the California Institute ofTechnology, and on observations obtained at the Lick Observatory, whichis operated by the University of California.
| A Strategy for Identifying the Grid Stars for the Space Interferometry Mission
We present a strategy to identify several thousand stars that areastrometrically stable at the microarcsecond level for use in the SpaceInterferometry Mission (SIM) astrometric grid. The requirements on thegrid stars make this a rather challenging task. Taking a variety ofconsiderations into account, we argue for K giants as the best type ofstars for the grid, mainly because they can be located at much largerdistances than any other type of star owing to their intrinsicbrightness. We show that it is possible to identify suitable candidategrid K giants from existing astrometric catalogs. However, double starshave to be eliminated from these candidate grid samples, since theygenerally produce much larger astrometric jitter than tolerable for thegrid. The most efficient way to achieve this is probably by means of aradial velocity survey. To demonstrate the feasibility of this approach,we repeatedly measured the radial velocities for a preselected sample of86 nearby Hipparcos K giants with precisions of 5-8 m s-1.The distribution of the intrinsic radial velocity variations for thebona fide single K giants shows a maximum around 20 m s-1,which is small enough not to severely affect the identification ofstellar companions around other K giants. We use the results of ourobservations as input parameters for Monte Carlo simulations on thepossible design of a radial velocity survey of all grid stars. Ourfavored scenario would result in a grid which consists to 68% of truesingle stars and to 32% of double or multiple stars with periods mostlylarger than 200 years, but only 3.6% of all grid stars would displayastrometric jitter larger than 1 μas. This contamination level isprobably tolerable.
| A catalog of rotational and radial velocities for evolved stars
Rotational and radial velocities have been measured for about 2000evolved stars of luminosity classes IV, III, II and Ib covering thespectral region F, G and K. The survey was carried out with the CORAVELspectrometer. The precision for the radial velocities is better than0.30 km s-1, whereas for the rotational velocity measurementsthe uncertainties are typically 1.0 km s-1 for subgiants andgiants and 2.0 km s-1 for class II giants and Ib supergiants.These data will add constraints to studies of the rotational behaviourof evolved stars as well as solid informations concerning the presenceof external rotational brakes, tidal interactions in evolved binarysystems and on the link between rotation, chemical abundance and stellaractivity. In this paper we present the rotational velocity v sin i andthe mean radial velocity for the stars of luminosity classes IV, III andII. Based on observations collected at the Haute--Provence Observatory,Saint--Michel, France and at the European Southern Observatory, LaSilla, Chile. Table \ref{tab5} also available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Catalogs of temperatures and [Fe/H] averages for evolved G and K stars
A catalog of mean values of [Fe/H] for evolved G and K stars isdescribed. The zero point for the catalog entries has been establishedby using differential analyses. Literature sources for those entries areincluded in the catalog. The mean values are given with rms errors andnumbers of degrees of freedom, and a simple example of the use of thesestatistical data is given. For a number of the stars with entries in thecatalog, temperatures have been determined. A separate catalogcontaining those data is briefly described. Catalog only available atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Classification of Population II Stars in the Vilnius Photometric System. II. Results
The results of photometric classification of 848 true and suspectedPopulation II stars, some of which were found to belong to Population I,are presented. The stars were classified using a new calibrationdescribed in Paper I (Bartkevicius & Lazauskaite 1996). We combinethese results with our results from Paper I and discuss in greaterdetail the following groups of stars: UU Herculis-type stars and otherhigh-galactic-latitude supergiants, field red horizontal-branch stars,metal-deficient visual binaries, metal-deficient subgiants, stars fromthe Catalogue of Metal-deficient F--M Stars Classified Photometrically(MDPH; Bartkevicius 1993) and stars from one of the HIPPARCOS programs(Bartkevicius 1994a). It is confirmed that high galactic latitudesupergiants from the Bartaya (1979) catalog are giants or even dwarfs.Some stars, identified by Rose (1985) and Tautvaisiene (1996a) as fieldRHB stars, appear to be ordinary giants according to our classification.Some of the visual binaries studied can be considered as physical pairs.Quite a large fraction of stars from the MDPH catalog are found to havesolar metallicity. A number of new possible UU Herculis-type stars, RHBstars and metal-deficient subgiants are identified.
| A catalogue of [Fe/H] determinations: 1996 edition
A fifth Edition of the Catalogue of [Fe/H] determinations is presentedherewith. It contains 5946 determinations for 3247 stars, including 751stars in 84 associations, clusters or galaxies. The literature iscomplete up to December 1995. The 700 bibliographical referencescorrespond to [Fe/H] determinations obtained from high resolutionspectroscopic observations and detailed analyses, most of them carriedout with the help of model-atmospheres. The Catalogue is made up ofthree formatted files: File 1: field stars, File 2: stars in galacticassociations and clusters, and stars in SMC, LMC, M33, File 3: numberedlist of bibliographical references The three files are only available inelectronic form at the Centre de Donnees Stellaires in Strasbourg, viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5), or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The photoelectric astrolabe catalogue of Yunnan Observatory (YPAC).
The positions of 53 FK5, 70 FK5 Extension and 486 GC stars are given forthe equator and equinox J2000.0 and for the mean observation epoch ofeach star. They are determined with the photoelectric astrolabe ofYunnan Observatory. The internal mean errors in right ascension anddeclination are +/- 0.046" and +/- 0.059", respectively. The meanobservation epoch is 1989.51.
| 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.
| High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances
A high-resolution spectroscopic survey of 671 G and K field giants isdescribed. Broad-band Johnson colors have been calibrated againstrecent, accurate effective temperature, T(eff), measurements for starsin the range 3900-6000 K. A table of polynomial coefficients for 10color-T(eff) relations is presented. Stellar atmosphere parameters,including T(eff), log g, Fe/H, and microturbulent velocity, are computedfor each star, using the high-resolution spectra and various publishedphotometric catalogs. For each star, elemental abundances for a varietyof species have been computed using a LTE spectrum synthesis program andthe adopted atmosphere parameters.
| DDO, Cousins R-I, and photomultiplier scanner data for an analysis of very strong lined K giants
New DDO photometry and photomultiplier scanner data on a number ofsuper-metal-rich K giants are presented. The data provide information onblanketing, feature strengths, and stellar temperatures. Some of thescanner data are transformed to the Cousins R-I system and given withpreviously published measurements using this system.
| Radial velocities of standard stars
Radial-velocity observations obtained over a five-year period with theMcDonald Observatory photoelectric radial-velocity spectrometer arereported for those stars not known to be velocity variable. There are259 stars included in the 1650 observations of the spectral type rangeF0 to M0 and brighter than a V of 6.5 mag. For the best-observed 134stars, the standard error of the mean velocity is typically better than+ or - 0.9 km/s. Sixteen stars are shown to be constant to a sufficientlevel to warrant standard-star status. Six possible spectroscopicbinaries are found.
| E. W. Fick Observatory stellar radial velocity measurements. I - 1976-1984
Stellar radial velocity observations made with the large vacuumhigh-dispersion photoelectric radial velocity spectrometer at FickObservatory are reported. This includes nearly 2000 late-type starsobserved during 585 nights. Gradual modifications to this instrumentover its first eight years of operation have reduced the observationalerror for high-quality dip observations to + or - 0.8 km/s.
| On the change of period of Dy Pegasi
In the course of testing a 3-channel photon-counting, high-speedphotometer, we observed DY Peg on three nights, 1980 September 18, 19,and November 15, and obtained 7 light maxima. Combining with resultsobserved over the past 30 years, we re-calculated the formula for themaximum epoch to be Tmax = H.J.D.2432751.96182 + 0.072926362E - 2.28 × 10-13E2+/- 0.00008 +/-0.000000001 +/- 0.09 and the period decay rate to be (3.1+/- 0.1) ×10-8yr-1.
| Radial-velocity standard stars
The paper reports the results of applying an iterative procedure devisedto establish a set of velocity standard stars for monitoring thebehavior of the Fick Observatory photoelectric radial-velocityspectrometer. Data obtained during the first three years of observationwith this instrument are used to select a set of 200 velocity standardstars brighter than 7th magnitude of spectral types from late F to earlyM. All velocities have been reduced to the Fick Observatory system.
| Final catalogue of 229 photometric standards in UBV system near the selected areas 1-115
Not Available
| Abundances in late-type giants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&A....19..434G&db_key=AST
| The corrected magnitudes and colours of 278 stars near S.A. 1-139 in the UBV system
Not Available
| Spectral and Luminosity Classifications and Measurements of the Strength of Cyanogen Absorption for Late-Type Stars from Objective-Prism Spectra.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...134..809Y&db_key=AST
| Positions et Mouvements propres de 357 Etoiles de Repère de la Zone + 16° à + 18° pour l'époque et l'équinoxe 1950,0
Not Available
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| קבוצת-כוכבים: | פגסוס |
| התרוממות ימנית: | 23h10m42.60s |
| סירוב: | +17°35'40.0" |
| גודל גלוי: | 5.71 |
| מרחק: | 155.039 פארסק |
| תנועה נכונה: | 24.7 |
| תנועה נכונה: | -28 |
| B-T magnitude: | 7.425 |
| V-T magnitude: | 5.816 |
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