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Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars
This paper presents the catalogue and the method of determination ofaveraged quadratic effective magnetic fields < B_e > for 596 mainsequence and giant stars. The catalogue is based on measurements of thestellar effective (or mean longitudinal) magnetic field strengths B_e,which were compiled from the existing literature.We analysed the properties of 352 chemically peculiar A and B stars inthe catalogue, including Am, ApSi, He-weak, He-rich, HgMn, ApSrCrEu, andall ApSr type stars. We have found that the number distribution of allchemically peculiar (CP) stars vs. averaged magnetic field strength isdescribed by a decreasing exponential function. Relations of this typehold also for stars of all the analysed subclasses of chemicalpeculiarity. The exponential form of the above distribution function canbreak down below about 100 G, the latter value representingapproximately the resolution of our analysis for A type stars.Table A.1 and its references are only available in electronic form atthe 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/407/631 and Tables 3 to 9are only available in electronic form at http://www.edpsciences.org
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| 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 "F str 4077" star HD 177645 as a possible barium dwarf star
The abundances of 12 elements in the atmosphere of the "F str 4077" starHD 177645 have been determined from new spectroscopic observations withthe CCD camera and the model atmosphere method. The overabundance ofnitrogen found for this star indicates its possible relation to bariumdwarfs with anomalies in the chemical composition of their atmospheresdue to mass transfer from the more evolved companion in a binary system.As an object related to Ba stars and CH subgiants, HD 177645 with aneffective temperature Teff=7150K may also have anomalies in the chemicalcomposition characteristic of diffusion processes in chemically peculiarstars of the upper main sequence, as may be indicated by theoverabundance of sulfur in its atmosphere.
| The nature of the F STR λ4077 stars. V. Spectroscopic data
We report first high-resolution spectroscopic observations of 17 starsclassified F str λ4077 by Bidelman. They are compared todifferent types of stars, which have been observed at the same time,including 3 CH subgiants, 3 barium stars, 5 λ Bootis stars, Ap/Amstars, and normal main-sequence stars. The detailed equivalent widthsand abundances are given for all measured spectral lines, as well as themean abundance per species for each object. These data and theirsignificance are described in detail and discussed in an articlepublished in the Main Journal.
| The nature of the F STR lambda 4077 stars. 3: Spectroscopy of the barium dwarfs and other CP stars
The abundances of C, O, Al, Ca, iron-peak and s-process elements havebeen derived from high-resolution spectra for a sample of starsclassified as F str lambda 4077 by Bidelman. Among the 20 starsmentioned by Bidelman, we have discovered 8 barium dwarfs (or CHsubgiants, according to Bond's terminology), while a 9th star, HD182274, was already known as a CH subgiant. In addition, we haveanalyzed three barium stars taken from the list of Lu et al. (1983)which are probably dwarfs rather than giants, and three CH subgiants.The other 11 F str lambda 4077 stars resemble either the delta Delphinistars, since their iron abundance is enhanced while Ca is normal, or areprobably spectrum composites. A few Am, Ap, lambda Bootis and normalstars have been analyzed for comparison. In particular, we have includedthree lambda Boo candidates, selected from their photometric properties,and their iron deficiency is confirmed. The spectroscopic, photometricand statistical evidences concerning the Ba dwarfs, support the ideathat these stars may be the main sequence counterparts, and possibly theprogenitors of the Ba giants. The C/O ratio varies in these stars fromnormal values to a maximum of 1.5, but mostly within 0.6 and 1.2. Someof these objects may therefore be considered, in this sense, as carbonstars. On the other hand, the abundances of carbon and s-processelements relative to iron are inversely correlated with metallicity, andmay even exceed significantly those of typical, solar-metallicity carbonstars. Metal-deficient C stars must therefore have (C/Fe) greater thanor approximately equal to 1 and (s/Fe) greater than or approximatelyequal to 1.5 as soon as (Fe/H) less than or approximately equal to -1.The neutron exposure is shown to increase when the metallicitydecreases, which is compatible with the C-13 (alpha, n) O-16 neutronsource, but not with the Ne-22 (alpha, n) Mg-25 one. The evolutionarystate (within the main sequence) of the Ba dwarfs, is rediscussed inrelation with their photometric and spectroscopic surface gravity, butit remains unclear.
| The nature of the F STR 4077-A stars. II - Frequency, kinematics, metallicity, binarity and rotational velocities
Fundamental characteristics of the F str 4077-A stars are investigated.Their frequency in the solar neighborhood is estimated at about 1.4percent of all main-sequence F stars. The space velocities areconsistent with Population I membership, with the exception of oneobject (in a sample of 17) whose velocity is above 100 km/s. The binaryfrequency is higher than normal, and the rotational velocities arenormal for the cooler stars but rather low for the hotter ones. Overallmetallicity, deduced from photometric and CORAVEL data, suggests adivision of these stars into two groups: metal-rich objects (generallythe hotter ones), which may resemble the Am or Ap stars, and slightlymetal-weak objects (generally the cooler ones), which may be linked withthe Ba II giants or the CH subgiants.
| The nature of the F STR lambda 4077 stars
Geneva photometry of seven stars classified F str 4077-A stars byBidelman (1981) is presented. Published uvby-beta measurements of fiveadditional stars of this type are used, as well to look for a possiblelink with the classical Am or Ap stars. It is shown that these starsexhibit a whole range of metallicities, the latter being correlated witheffective temperature. The existing proper motions point to a PopulationI membership, although one star seems to have a rather high velocity. Itis suggested that this new type of peculiarity may be interpreted in theframework of the diffusion theory and that at least some F str 4077-Astars may represent an intermediate stage between Am and Lambda Bootisstars, although they are generally cooler.
| Objective-prism discoveries in the northern sky - II.
Five tables list the observed characteristics of 244 northern hemispherestars recorded in 100 108 A/mm dispersion plates at H-gamma wavelengths.The 5 x 5 deg fields contained a number of suspected weak-metal objects.Listings are divided into peculiar A stars, metallic line and deltaDelphini stars, high luminosity objects, Ca II emission stars of the Gand K type, and composite spectra.
| The fourth meridian catalog of Besancon Observatory
The catalog presented gives differential meridian positions for 670F-type stars between plus 15 and plus 45 deg declination. The positionsare reduced to the equinox of 1950.0 without proper motions; 333 FK4stars were used as reference stars. A minimum of three and an average offive transits of each program star were observed photoelectrically usinga Gautier transit circle and a Hog grid. The internal accuracy ofindividual measurements is shown to range from 0.013 sec in rightascension and 0.30 arcsec in declination for brighter stars under betterobserving conditions to 0.020 sec in right ascension and 0.38 arcsec indeclination for fainter stars under worse conditions. The standarderrors were applied to compute weighted mean positions, mean epochs, andunweighted means for the program stars. Mean corrections for 283 FK4stars are also provided.
| 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.
| Photoelectric UBV photometry in some Milky Way fields
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...11..365W&db_key=AST
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Группы:
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Наблюдательные данные и астрометрия
| Созвездие: | Лира |
| Прямое восхождение: | 19h04m12.23s |
| Склонение: | +33°19'16.6" |
| Видимая звёздная величина: | 7.702 |
| Расстояние: | 383.142 парсек |
| Собственное движение RA: | 2.1 |
| Собственное движение Dec: | -6.5 |
| B-T magnitude: | 8.129 |
| V-T magnitude: | 7.738 |
Каталоги и обозначения:
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