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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| A catalog of bright calibrator stars for 200-m baseline near-infrared stellar interferometry
We present in this paper a catalog of reference stars suitable forcalibrating infrared interferometric observations. In the K band,visibilities can be calibrated with a precision of 1% on baselines up to200 meters for the whole sky, and up to 300 meters for some part of thesky. This work, extending to longer baselines a previous catalogcompiled by Bordé et al. (2002, A&A, 393, 183), isparticularl y well adapted to hectometric-class interferometers such asthe Very Large Telescope Interferometer (VLTI, Glindemann et al. 2003,Proc. SPIE, 4838, 89) or the CHARA array (ten Brummelaar et al. 2003,Proc. SPIE, 4838, 69) when one is observing well-resolved, high-surfacebrightness objects (K 8). We use the absolute spectro-photometriccalibration method introduced by Cohen et al. (1999, AJ, 117, 1864) toderive the angular diameters of our new set of 948 G8-M0 calibratorstars extracted from the IRAS, 2MASS and MSX catalogs. Angular stellardiameters range from 0.6 mas to 1.8 mas (median is 1.1 mas) with amedian precision of 1.35%. For both the northern and southernhemispheres, the closest calibrator star is always less than 10°away.
| CHARM2: An updated Catalog of High Angular Resolution Measurements
We present an update of the Catalog of High Angular ResolutionMeasurements (CHARM, Richichi & Percheron \cite{CHARM}, A&A,386, 492), which includes results available until July 2004. CHARM2 is acompilation of direct measurements by high angular resolution methods,as well as indirect estimates of stellar diameters. Its main goal is toprovide a reference list of sources which can be used for calibrationand verification observations with long-baseline optical and near-IRinterferometers. Single and binary stars are included, as are complexobjects from circumstellar shells to extragalactic sources. The presentupdate provides an increase of almost a factor of two over the previousedition. Additionally, it includes several corrections and improvements,as well as a cross-check with the valuable public release observationsof the ESO Very Large Telescope Interferometer (VLTI). A total of 8231entries for 3238 unique sources are now present in CHARM2. Thisrepresents an increase of a factor of 3.4 and 2.0, respectively, overthe contents of the previous version of CHARM.The catalog is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/431/773
| 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}
| The Extinction and Distance of Maffei 1
We have obtained low- and high-resolution spectra of the core of thehighly reddened elliptical galaxy Maffei 1. From these data, we haveobtained the first measurement of the Mg2 index and havemeasured the velocity dispersion and radial velocity with improvedaccuracy. To evaluate the extinction, a correlation between theMg2 index and effective V-I color has been established forelliptical galaxies. Using a new method for correcting for effectivewavelength shifts, the V-I color excess reveals that the optical depthof Galactic dust at 1 μm is 1.69+/-0.07. Thus,AV=4.67+/-0.19 mag, which is lower by 0.4 mag than previouslythought. To establish the distance, the fundamental plane for ellipticalgalaxies has been constructed in I. The velocity dispersion of Maffei 1,measured to be 186.8+/-7.4 km s-1, in combination with modernwide-field photometry in I, leads to a distance of 2.92+/-0.37 Mpc. TheDn-σ relation, which is independently calibrated, gives3.08+/-0.85 and 3.23+/-0.67 Mpc from photometry in B and K',respectively. The weighted mean of the three estimates is 3.01+/-0.30Mpc, which is lower than distances judged with reference to M32 and thebulge of M31 from the brightest stars seen at K'. Since the luminosityof asymptotic giant branch stars at K' is strongly dependent on age, thelower distance suggests that the last epoch of star formation in Maffei1 occurred farther in the past than in these other systems. The distanceand luminosity make Maffei 1 the nearest giant elliptical galaxy. In theabsence of extinction, the galaxy would be among the brightest in thesky and would have an apparent size 2/3 that of the full Moon. Theradial velocity of Maffei 1 is +66.4+/-5.0 km s-1,significantly higher than the accepted value of -10 km s-1.The Hubble distance corresponding to the mean velocity of Maffei 1,Maffei 2, and IC 342 is 3.5 Mpc. Thus, it is unlikely that Maffei 1 hashad any influence on Local Group dynamics.
| Radial velocity measurements. II - Ground-based observations of the program stars for the HIPPARCOS satellite
New radial velocities for 446 stars of magnitude 9.0 or brighter in 1616-sq-deg fields of the Northern Hemisphere are determined by automaticPDS measurement of 80-A/mm-dispersion spectra obtained at theObservatoire de Haute Provence using a 17-cm-diameter objective prism.The fields were selected to provide data for the input catalog of theESA Hipparcos astrometric satellite. The measurement techniques andprecision are discussed, and the results are presented in extensivetables and graphs.
| A comparison between Washington and DDO photometry of field red giants
Washington CMT1T2 photometry of a sample of field red giants is comparedwith DDO colors obtained by McClure (1970) and Janes (1975) to determinethe relative sensitivities of the metallicity indices of the twosystems. Washington line-blanketing indices delta(M-T1) and delta(C-M)were derived, and found to correlate very well with each other, inaddition to correlating quite well with the DDO metallicity index.Furthermore, any N/A or C/A abundance variations which may exist amongthe present sample of old disk giants do not appear to significantlyeffect the delta(C-M) index. The study indicates that delta(C-M) shouldprovide a useful photometric metal abundance indicator, and is capableof providing estimates accurate to about + or - 0.2 dex over the Fe/Habundance range of +0.4 to -0.8.
| Stars with Strong Cyanogen Absorption
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJ...163...75S&db_key=AST
| A photoelectric investigation of strong cyanogen stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970AJ.....75...41M&db_key=AST
| 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
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Osservazione e dati astrometrici
| Costellazione: | Giraffa |
| Ascensione retta: | 04h21m03.60s |
| Declinazione: | +56°42'44.0" |
| Magnitudine apparente: | 7.079 |
| Distanza: | 384.615 parsec |
| Moto proprio RA: | -4.6 |
| Moto proprio Dec: | -7.1 |
| B-T magnitude: | 8.951 |
| V-T magnitude: | 7.234 |
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INHABITED SKY
