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Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| A photometric and spectroscopic study of the brightest northern Cepheids - I. Observations
We present simultaneous UBVuvby photometry for the 18 brightest northernCepheids carried out between 1995 and 1997. Additionally, two fainterstars have been observed in the Johnson system only. The wholephotometric data base contains about 3500 individual data points for 20stars. The accuracy has been carefully tested with different methods. Aserious systematic difference has been found between the present dataset and the Stromgren photometry available in the literature, which hasprobably been caused by the peculiar filter set used in the earlierstudy. As an extension to the photometry, we took high-resolutionoptical spectra at David Dunlap Observatory in the red spectral region(lambda/Deltalambda~ 40000, in the interval of 6200and6600Angstromsincluding Hα). The spectroscopic programme contained 12stars from the photometric programme, the newly discovered brightclassical Cepheid CK Cam and two double-mode Cepheids (TU Cas and COAur). New radial velocities obtained with the cross-correlationtechnique are presented. We found significant velocity differencesbetween two cross-correlated spectral regions (6188-6220and 6405-6435Angstroms) as large as 0.8-1.2 km s^-1, which show very characteristicphase dependence in certain Cepheids. Finally, recent period variationsare briefly discussed in terms of phase jumps and duplicity.
| 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.
| Stroemgren photometry of F- and G-type stars brighter than V = 9.6. I. UVBY photometry
Within the framework of a large photometric observing program, designedto investigate the Galaxy's structure and evolution, Hβ photometryis being made for about 9000 stars. As a by-product, supplementary uvbyphotometry has been made. The results are presented in a cataloguecontaining 6924 uvby observations of 6190 stars, all south ofδ=+38deg. The overall internal rms errors of one observation(transformed to the standard system) of a program star in the interval6.5
| Radial-velocity measurements. V - Ground support of the HIPPARCOS satellite observation program
The paper presents data on 1070 radial velocity measurements of starsdistributed in 39 fields measuring 4 deg x 4 deg. The PPO series ofFehrenbach et al. (1987) and Duflot et al. (1990) is continued using theFehrenbach objective prism method.
| 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.
| Double star observations made with the 28-inch refractor 1963-1970.
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Osservazione e dati astrometrici
| Costellazione: | Gemelli |
| Ascensione retta: | 06h32m20.69s |
| Declinazione: | +15°42'22.3" |
| Magnitudine apparente: | 7.233 |
| Distanza: | 148.588 parsec |
| Moto proprio RA: | 0.3 |
| Moto proprio Dec: | -6.3 |
| B-T magnitude: | 8.044 |
| V-T magnitude: | 7.3 |
Cataloghi e designazioni:
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