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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
| STELIB: A library of stellar spectra at R ~ 2000
We present STELIB, a new spectroscopic stellar library, available athttp://webast.ast.obs-mip.fr/stelib. STELIB consists of an homogeneouslibrary of 249 stellar spectra in the visible range (3200 to 9500Å), with an intermediate spectral resolution (la 3 Å) andsampling (1 Å). This library includes stars of various spectraltypes and luminosity classes, spanning a relatively wide range inmetallicity. The spectral resolution, wavelength and spectral typecoverage of this library represents a substantial improvement overprevious libraries used in population synthesis models. The overallabsolute photometric uncertainty is 3%.Based on observations collected with the Jacobus Kaptein Telescope,(owned and operated jointly by the Particle Physics and AstronomyResearch Council of the UK, The Nederlandse Organisatie voorWetenschappelijk Onderzoek of The Netherlands and the Instituto deAstrofísica de Canarias of Spain and located in the SpanishObservatorio del Roque de Los Muchachos on La Palma which is operated bythe Instituto de AstrofÃsica de Canarias), the 2.3 mtelescope of the Australian National University at Siding Spring,Australia, and the VLT-UT1 Antu Telescope (ESO).Tables \ref{cat1} to \ref{cat6} and \ref{antab1} to A.7 are onlyavailable in electronic form at http://www.edpsciences.org. The StellarLibrary STELIB library is also available at the CDS, via anonymous ftpto cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/402/433
| Wind circulation in selected rotating magnetic early-B stars
The rotating magnetic B stars are a class of variables consisting ofHe-strong and some beta Cep stars which have oblique dipolar magneticfields. Such stars develop co-rotating, torus-shaped clouds bychanneling wind particles from their magnetic poles to circumstellarregions centered around the plane of their magnetic equators. Therotation of the cloud-star complex permits the study of absorptions fromthe cloud as it occults the star. In this paper we describe aquantitative analysis of archival IUE data to map the properties ofthese clouds over four stars (HD 184927, sigma Ori E, beta Cep, and HR6684). By computing spectral synthesis models for these stars, we findthat only beta Cep has a solar-like metallicity. Our analysis also showsthat the metal composition across the surfaces of all these stars is atleast approximately homogeneous. Using the Hubeny code CIRCUS, wedemonstrate that the periodic variations of broad-band ultravioletcontinuum fluxes can be explained fully by the absorptions of theco-rotating cloud. We show next that among selected lines, those arisingfrom low-excitation states are selectively affected by cloud absorptionand turbulence. Our analysis also quantifies the cloud temperatures andcolumn densities required to match the absorptions of a number of weakto moderate strength resonance lines. These temperatures increase withthe ionization potential of the parent ions of these various lines, aresult which is consistent with radiative equilibrium models in whichtemperature increases with proximity to the star's surface. Althoughthese attributes appear stable from one epoch to another, dynamicprocesses are nonetheless at work. Both the strengths and widths ofresonance lines at occultation phases indicate the presence of aturbulence in the cloud which increases inwards. The spectroscopichallmark of this stellar class is the presence of strong C IV and N Vresonance line absorptions at occultation phases and of redshiftedemissions of these lines at magnetic pole-on phases. The emissions havecharacteristics which seem most compatible with their generation byhigh-energy shocks at the wind-cloud interface, as predicted recently byBabel (\cite{bab}).
| On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Helium peculiar stars in the red spectral region
Based upon 33 A/mm dispersion spectroscopic material we examine ifequivalent widths of H and He lines can be used for the detection of newhelium-peculiar stars. The answer is affirmative and we present some newcandidates discovered this way. We have also investigated if the use ofdifferent helium lines than those of the (3) D series (4026, 4471)modifies the assignments of helium peculiar stars. This is not the case,since the use of lambda 6678 ((1) D) and lambda 7065 (3S) gives the sameresults. Based on observations obtained at the Haute ProvenceObservatory (CNRS)
| The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars
The HR-diagram of about 1000 Bp - Ap stars in the solar neighbourhoodhas been constructed using astrometric data from Hipparcos satellite aswell as photometric and radial velocity data. The LM method\cite{luri95,luri96} allows the use of proper motion and radial velocitydata in addition to the trigonometric parallaxes to obtain luminositycalibrations and improved distances estimates. Six types of Bp - Apstars have been examined: He-rich, He-weak, HgMn, Si, Si+ and SrCrEu.Most Bp - Ap stars lie on the main sequence occupying the whole width ofit (about 2 mag), just like normal stars in the same range of spectraltypes. Their kinematic behaviour is typical of thin disk stars youngerthan about 1 Gyr. A few stars found to be high above the galactic planeor to have a high velocity are briefly discussed. Based on data from theESA Hipparcos astrometry satellite and photometric data collected in theGeneva system at ESO, La Silla (Chile) and at Jungfraujoch andGornergrat Observatories (Switzerland). Tables 3 and 4 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
| The observed periods of AP and BP stars
A catalogue of all the periods up to now proposed for the variations ofCP2, CP3, and CP4 stars is presented. The main identifiers (HD and HR),the proper name, the variable-star name, and the spectral type andpeculiarity are given for each star as far as the coordinates at 2000.0and the visual magnitude. The nature of the observed variations (light,spectrum, magnetic field, etc.) is presented in a codified way. Thecatalogue is arranged in three tables: the bulk of the data, i.e. thosereferring to CP2, CP3, and CP4 stars, are given in Table 1, while thedata concerning He-strong stars are given in Table 2 and those foreclipsing or ellipsoidal variables are collected in Table 3. Notes arealso provided at the end of each table, mainly about duplicities. Thecatalogue contains data on 364 CP stars and is updated to 1996, October31. This research has made use of the SIMBAD database, operated at CDS,Strasbourg, France.
| Age variation of helium abundance in He-rich stars.
Not Available
| 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 magnetic field and helium variation of the helium-strong star HD 184927.
We have obtained 29 longitudinal magnetic field measurements of thehelium-strong star HD 184927 using the University of Western Ontariophotoelectric polarimeter and the Special Astrophysical ObservatoryZeeman Analyzer. These measurements, obtained over ~5500-days, confirmthe presence of a variable line-of-sight magnetic field. A period searchof these data reveals several acceptable rotational periods, the mostsignificant of which is 9.52961d +/-0.00731d. This period is the onlyone consistent with those determined previously from analysis ofphotometric, equivalent width and magnetic variations (Bond & Levato1976PASP...88..905B; Levato & Malaroda 1979PASP...91..789L). Whenphased with this period, the longitudinal field data describe a smoothsinusoidal curve with extrema of -0.7kG and +1.8kG. When we phase thehelium equivalent width measurements and u-band photometry of Bond &Levato (1976PASP...88..905B) with our adopted period, the maximum ofeach of these quantities occurs at the same phase as the longitudinalfield maximum. This indicates that an enhanced patch of helium may existin the photosphere of HD 184927 near the positive magnetic pole. Thereis no evidence for such an enhancement near the negative pole. Thissuggests that significant differences may exist in the magnetic field ofHD 184927 at the positive and negative magnetic poles, consistent withthe presence of an important magnetic quadrupole component. Bysynthesizing C II λ6582.9 at a single phase, we have attempted,with moderate success, to define the magnetic field geometry. Using theline profile morphology, the observed longitudinal field variation, anthe position of HD 184927 on the logT_eff_-logg diagram (which implies aradius R=6.6+/-0.8Rsun_), we find the projected rotationalvelocity v_e_sin i=14.5+/-2.5km/s, the inclination of the rotationalaxis to the line-of-sight i=25+/-5°, and the obliquity of themagnetic symmetry axis β=78+/-3°. Possible magneticconfigurations range from nearly dipolar, to those which containquadrupole and octupole components comparable in polar strength to thedipole component.
| 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.
| Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
| An IUE survey of interstellar H I LY alpha absorption. 1: Column densities
We measure Galactic interstellar neutral hydrogen column densities byanalyzing archival interstellar Ly alpha absorption line data toward 554B2 and hotter stars observed at high resolution with the IUE satellite.This study more than doubles the number of lines of sight with measuresof N(H I) based on Ly alpha. We have included the scattered lightbackground correction algorithm of Bianchi and Bohlin in our datareduction. We use the correlation between the Balmer discontinuity(c1) index and the stellar Ly alpha absorption in order toassess the effects of stellar Ly alpha contamination. Approximately 40%of the B stars with measured (c1) index, exhibit seriousstellar Ly alpha contamination. One table contains the derived values ofthe interstellar N(H I) for 393 stars with at most small amounts ofstellar contamination. Another lists the observed values of total N(H I)for 161 stars with suspected stellar Ly alpha contamination and/oruncertain stellar parameters.
| Catalogue of CP stars with references to short time scale variability
A catalogue was compiled which contains all references in the literaturesince 1962 related to variations of CP stars on time scales shorter thanthe rotation period. The role of this catalogue lies in the unbiasedlisting of all available references, and not in a critical evaluation.
| Radio Emission from Magnetic Chemically Peculiar Stars - Results of the 1992 VLA Survey
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1994A&A...283..908L&db_key=AST
| A new list of effective temperatures of chemically peculiar stars. II.
Not Available
| A catalogue of Fe/H determinations - 1991 edition
A revised version of the catalog of Fe/H determinations published by G.Cayrel et al. (1985) is presented. The catalog contains 3252 Fe/Hdeterminations for 1676 stars. The literature is complete up to December1990. The catalog includes only Fe/H determinations obtained from highresolution spectroscopic observations based on detailed spectroscopicanalyses, most of them carried out with model atmospheres. The catalogcontains a good number of Fe/H determinations for stars from open andglobular clusters and for some supergiants in the Magellanic Clouds.
| Mid-ultraviolet and optical photometry of helium stars
Mid-ultraviolet and optical photometric analysis of helium stars arepresented. A linear relation exists between the effective temperaturederived from model atmospheres and (1965-V)0 index. The effectivetemperatures derived from (1965-V)0 index are somewhat higher than thatof MK spectral type estimates especially for late B-type helium objects.
| Helium inhomogeneities in main-sequence magnetic stars
Helium abundance variations are computed in models of main-sequencemagnetic stars with masses in the range 1.6-5 solar mass (Teff =8,000-19,000 K). To represent a predominantly dipolar magnetic field,regions in the stars are schematically designated either polar, withvertical magnetic fields, or equatorial, with horizontal fields. Astellar wind is supposed to exist at the magnetic poles. The mass-lossrate is varied as a free parameter in the computations. Under theseconditions, helium is underabundant at the magnetic equators, while itcan accumulate at the poles in the region of the first ionization ofhelium. The accumulation occurs if the mass-loss rate is of the order ofthat caused by the solar wind. The helium peak is visible in theatmospheres of the hottest stars, which can account for the observedHe-rich stars. It lies below the photosphere and should not be visiblein the coolest stars; but it can help to excite the pulsations ofrapidly oscillating Ap stars by the Kappa mechanism.
| Second supplement to the catalogue of observed periods of AP stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1991A&AS...87...59C&db_key=AST
| Average Profiles and Equivalent Widths of Hydrogen Lines of 76 Normal and Peculiar Stars - Masses and Radii of Studied Stars
Not Available
| On dependence of helium abundance upon magnetic field in He-r stars.
Not Available
| Surface inhomogenities and multiperiodic phenomena in Be and BP stars.
Not Available
| Magnetic Fields and Other Parameters of Chemically Peculiar Stars - Part Two
Not Available
| The Relation Between Magnetic Field Strength and Helium Abundance in Helium Rich Stars
Not Available
| Empirical temperature calibrations for early-type stars
Three temperature calibrations of suitable photometric quantities havebeen derived for O and B stars. A sample of 120 stars with reliableT(eff.) determinations has been used for establishing each calibration.The different calibrations have been critically discussed and compared.Temperature determinations for 1009 program stars have been obtainedwith an accuracy of the order of 10 percent.
| Search for Short Time Scale Light Variation in HD 183339 and HD 184927
Not Available
| The nitrogen abundance in the atmospheres of single and binary stars
The nitrogen abundances for 47 single, 11 visual double, and 41 closebinary stars are obtained from high-dispersion Wlambdadeterminations of nitrogen lines using atmospheric models andtheoretical calculations of N II lines, taking LTE errors into account.The mean value of lg N(N) is found to be 8.05 for single stars, 8.50 forclose binaries, and 8.15 for visual double stars. A correlation is foundbetween the nitrogen abundance and the helium and carbon abundances. Itis suggested that considerable mixing between the central part of starsand the atmosphere occurs in binary stars.
| First supplement to the catalog of observed periods of AP stars
Supplementary data on the periods of Ap stars with references arepresented; 58 new stars are introduced for which periodic variabilityhas been discovered since 1983. For some of these stars periodicity wasknown before 1983 but they were not reported in the previous catalog.Recently attributed variable star names are also reported.
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Pozíciós és asztrometriai adatok
| Csillagkép: | Hattyú |
| Rektaszcenzió: | 19h35m32.01s |
| Deklináció: | +31°16'35.9" |
| Vizuális fényesség: | 7.441 |
| Távolság: | 558.659 parszek |
| RA sajátmozgás: | 5.4 |
| Dec sajátmozgás: | 5.8 |
| B-T magnitude: | 7.243 |
| V-T magnitude: | 7.425 |
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