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A high-resolution spectroscopy survey of β Cephei pulsations in bright stars
We present a study of absorption line-profile variations in early-B typenear-main-sequence stars without emission lines. We have surveyed atotal of 171 bright stars using the Nordic Optical Telescope (NOTSA),William Herschel Telescope (ING) and Coudé Auxiliary Telescope(ESO). Our sample contains 75% of all O9.5-B2.5 III-V non-emission-linestars brighter than 5.5 mag. We obtained high signal-to-noise,high-resolution spectra of the SiIII λ4560 triplet - for 125stars of our sample we obtained more than one spectrum - and examinedthese for pulsational-like line-profile variations and/or structure. Weconclude that about half of our sample stars show evidence forline-profile variations (LPV). We find evidence for LPV in about 65% ofour sample stars brighter than V=5.5. For stars with rotationalbroadening V sin i 100 km s-1, we find evidence for LPVin about 75% of the cases. We argue that it is likely that these LPV areof pulsational origin, and that hence more than half of thesolar-neighbourhood O9.5-B2.5 III-V stars is pulsating in modes that canbe detected with high-resolution spectroscopy. We detected LPV in 64stars previously unknown to be pulsators, and label these stars as newβ Cep candidates. We conclude that there is no obvious differencein incidence of (pulsational) LPV for early-B type near-main-sequencestars in binaries or in OB associations, with respect to single fieldstars.
| Evolution of interacting binaries with a B type primary at birth
We revisited the analytical expression for the mass ratio distributionfor non-evolved binaries with a B type primary. Selection effectsgoverning the observations were taken into account in order to comparetheory with observations. Theory was optimized so as to fit best withthe observed q-distribution of SB1s and SB2s. The accuracy of thistheoretical mass ratio distribution function is severely hindered by theuncertainties on the observations. We present a library of evolutionarycomputations for binaries with a B type primary at birth. Some liberalcomputations including loss of mass and angular momentum during binaryevolution are added to an extensive grid of conservative calculations.Our computations are compared statistically to the observeddistributions of orbital periods and mass ratios of Algols. ConservativeRoche Lobe Over Flow (RLOF) reproduces the observed distribution oforbital periods but fails to explain the observed mass ratios in therange q in [0.4-1]. In order to obtain a better fit the binaries have tolose a significant amount of matter, without losing much angularmomentum.
| Astrophysical parameters for the eclipsing binary u Herculis
Not Available
| The epoch of the constellations on the Farnese Atlas and their origin in Hipparchus's lost catalogue
Not Available
| Observed Orbital Eccentricities
For 391 spectroscopic and visual binaries with known orbital elementsand having B0-F0 IV or V primaries, we collected the derivedeccentricities. As has been found by others, those binaries with periodsof a few days have been circularized. However, those with periods up toabout 1000 or more days show reduced eccentricities that asymptoticallyapproach a mean value of 0.5 for the longest periods. For those binarieswith periods greater than 1000 days their distribution of eccentricitiesis flat from 0 to nearly 1, indicating that in the formation of binariesthere is no preferential eccentricity. The binaries with intermediateperiods (10-100 days) lack highly eccentric orbits.
| Heavy Element Abundances in Late-B and Early-A Stars. I. Co-Added IUE Spectra of HgMn Stars
Very heavy elements (Pt, Au, Hg, Tl, and Bi) are found to be enhanced inthe atmospheres of the chemically peculiar stars of the upper mainsequence by up to a million times the solar system levels. Suchenhancements are believed to result from atmospheric dynamics (i.e.,diffusion) rather than scenarios that dredge up nuclear-processedmaterial to the surface or transfer processed material between binarycompanions. However, the theoretical framework needs to be furtherconstrained by observations beyond the realm of the spectral types forwhich such abundance enhancements are observed at optical wavelengths.The International Ultraviolet Explorer (IUE) satellite collected spectraof bright stars for which chemical peculiarities have been derived fromground-based data. For several elements the abundance enhancements haveonly been recently measured using Hubble Space Telescope data and havetherefore not yet been exploited in the IUE data. We have initiated aprogram to analyze IUE high-dispersion spectra to more fullycharacterize the pattern of very heavy element enhancement for manymercury-manganese (HgMn) stars and to potentially extend the spectralclass (effective temperature) boundaries over which these abundanceanomalies are known to exist. The abundances of very heavy elements inchemically normal B and A-type stars provide a base level that may becompared with the solar system abundances. These early spectral typestars may therefore reveal clues for galactic chemical evolution studiessince they were formed at a later epoch than the Sun in the history ofthe Galaxy. This first paper presents the motivation for the analyses tofollow, outlines our spectral co-addition technique for IUE spectra, anddiscusses the choice of model atmospheres and the synthetic spectrumprocedures, while initiating the study by highlighting the abundance ofgold in several HgMn stars.
| The Indo-US Library of Coudé Feed Stellar Spectra
We have obtained spectra for 1273 stars using the 0.9 m coudéfeed telescope at Kitt Peak National Observatory. This telescope feedsthe coudé spectrograph of the 2.1 m telescope. The spectra havebeen obtained with the no. 5 camera of the coudé spectrograph anda Loral 3K×1K CCD. Two gratings have been used to provide spectralcoverage from 3460 to 9464 Å, at a resolution of ~1 Å FWHMand at an original dispersion of 0.44 Å pixel-1. For885 stars we have complete spectra over the entire 3460 to 9464 Åwavelength region (neglecting small gaps of less than 50 Å), andpartial spectral coverage for the remaining stars. The 1273 stars havebeen selected to provide broad coverage of the atmospheric parametersTeff, logg, and [Fe/H], as well as spectral type. The goal ofthe project is to provide a comprehensive library of stellar spectra foruse in the automated classification of stellar and galaxy spectra and ingalaxy population synthesis. In this paper we discuss thecharacteristics of the spectral library, viz., details of theobservations, data reduction procedures, and selection of stars. We alsopresent a few illustrations of the quality and information available inthe spectra. The first version of the complete spectral library is nowpublicly available from the National Optical Astronomy Observatory(NOAO) via ftp and http.
| Tidal Effects in Binaries of Various Periods
We found in the published literature the rotational velocities for 162B0-B9.5, 152 A0-A5, and 86 A6-F0 stars, all of luminosity classes V orIV, that are in spectroscopic or visual binaries with known orbitalelements. The data show that stars in binaries with periods of less thanabout 4 days have synchronized rotational and orbital motions. Stars inbinaries with periods of more than about 500 days have the samerotational velocities as single stars. However, the primaries inbinaries with periods of between 4 and 500 days have substantiallysmaller rotational velocities than single stars, implying that they havelost one-third to two-thirds of their angular momentum, presumablybecause of tidal interactions. The angular momentum losses increase withdecreasing binary separations or periods and increase with increasingage or decreasing mass.
| 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
| Elemental abundance analyses with the EBASIM spectrograph of the 2.1-m CASLEO Observatory Telescope. I. The late B and early A stars vec xi Octantis, alpha Sextantis, and 68 Tauri
We used data from the EBASIM spectrograph of the 2.1-m CASLEO telescopeto study three rather sharp-lined late B to early A stars xi Oct (B6IV), alpha Sex (B9.5 III), and 68 Tau (A2 IV). These measurements arecompared with those from the Anglo-Austrialian Telescope for the firststar and to those from the coudé spectrograph of the 1.22-mtelescope of the Dominion Astrophysical Observatory (DAO) for the othertwo stars. The equivalent width scales of the EBASIM and the DAO dataare similar. Thus for the latter two stars the DAO data is also used inthe analyses. Both xi Oct and alpha Sex generally have abundancesclose to those of the Sun in the range of values found for other normalstars with similar effective temperatures. The abundance pattern for 68Tau is that of a metallic-lined star as is well known.Tables 5 to 7 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/406/987
| Quantitative Stellar Spectral Classification. II. Early Type Stars
The method developed by Stock & Stock (1999) for stars of spectraltypes A to K to derive absolute magnitudes and intrinsic colors from theequivalent widths of absorption lines in stellar spectra is extended toB-type stars. Spectra of this type of stars for which the Hipparcoscatalogue gives parallaxes with an error of less than 20% were observedwith the CIDA one-meter reflector equipped with a Richardsonspectrograph with a Thompson 576×384 CCD detector. The dispersionis 1.753 Å/pixel using a 600 lines/mm grating in the first order.In order to cover the spectral range 3850 Å to 5750 Å thegrating had to be used in two different positions, with an overlap inthe region from 4800 Å to 4900 Å . A total of 116 stars wasobserved, but not all with both grating positions. A total of 12measurable absorption lines were identified in the spectra and theirequivalent widths were measured. These were related to the absolutemagnitudes derived from the Hipparcos catalogue and to the intrinsiccolors (deduced from the MK spectral types) using linear and secondorder polynomials and two or three lines as independent variables. Thebest solutions were obtained with polynomials of three lines,reproducing the absolute magnitudes with an average residual of about0.40 magnitudes and the intrinsic colors with an average residual of0.016 magnitudes.
| New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
| Rotational Velocities of B Stars
We measured the projected rotational velocities of 1092 northern B starslisted in the Bright Star Catalogue (BSC) and calibrated them againstthe 1975 Slettebak et al. system. We found that the published values ofB dwarfs in the BSC average 27% higher than those standards. Only 0.3%of the stars have rotational velocities in excess of two-thirds of thebreakup velocities, and the mean velocity is only 25% of breakup,implying that impending breakup is not a significant factor in reducingrotational velocities. For the B8-B9.5 III-V stars the bimodaldistribution in V can be explained by a set of slowly rotating Ap starsand a set of rapidly rotating normal stars. For the B0-B5 III-V starsthat include very few peculiar stars, the distributions in V are notbimodal. Are the low rotational velocities of B stars due to theoccurrence of frequent low-mass companions, planets, or disks? Therotational velocities of giants originating from late B dwarfs areconsistent with their conservation of angular momentum in shells.However, we are puzzled by why the giants that originate from the earlyB dwarfs, despite having 3 times greater radii, have nearly the samerotational velocities. We find that all B-type primaries in binarieswith periods less than 2.4 days have synchronized rotational and orbitalmotions; those with periods between 2.4 and 5.0 days are rotating withina factor 2 of synchronization or are ``nearly synchronized.'' Thecorresponding period ranges for A-type stars are 4.9 and 10.5 days, ortwice as large. We found that the rotational velocities of the primariesare synchronized earlier than their orbits are circularized. The maximumorbital period for circularized B binaries is 1.5 days and for Abinaries is 2.5 days. For stars of various ages from 107.5 to1010.2 yr the maximum circularized periods are a smoothexponential function of age.
| Astrometric radial velocities. III. Hipparcos measurements of nearby star clusters and associations
Radial motions of stars in nearby moving clusters are determined fromaccurate proper motions and trigonometric parallaxes, without any use ofspectroscopy. Assuming that cluster members share the same velocityvector (apart from a random dispersion), we apply a maximum-likelihoodmethod on astrometric data from Hipparcos to compute radial and spacevelocities (and their dispersions) in the Ursa Major, Hyades, ComaBerenices, Pleiades, and Praesepe clusters, and for theScorpius-Centaurus, alpha Persei, and ``HIP 98321'' associations. Theradial motion of the Hyades cluster is determined to within 0.4 kms-1 (standard error), and that of its individual stars towithin 0.6 km s-1. For other clusters, Hipparcos data yieldastrometric radial velocities with typical accuracies of a few kms-1. A comparison of these astrometric values withspectroscopic radial velocities in the literature shows a good generalagreement and, in the case of the best-determined Hyades cluster, alsopermits searches for subtle astrophysical differences, such as evidencefor enhanced convective blueshifts of F-dwarf spectra, and decreasedgravitational redshifts in giants. Similar comparisons for the ScorpiusOB2 complex indicate some expansion of its associations, albeit slowerthan expected from their ages. As a by-product from the radial-velocitysolutions, kinematically improved parallaxes for individual stars areobtained, enabling Hertzsprung-Russell diagrams with unprecedentedaccuracy in luminosity. For the Hyades (parallax accuracy 0.3 mas), itsmain sequence resembles a thin line, possibly with wiggles in it.Although this main sequence has underpopulated regions at certaincolours (previously suggested to be ``Böhm-Vitense gaps''), suchare not visible for other clusters, and are probably spurious. Futurespace astrometry missions carry a great potential for absoluteradial-velocity determinations, insensitive to the complexities ofstellar spectra. Based on observations by the ESA Hipparcos satellite.Extended versions of Tables \ref{tab1} and \ref{tab2} are available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.125.8) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/381/446
| Der 8X50 Feldstecher ergantzt das Auge.
Not Available
| Boron Abundances in Early B Stars: Results from the B III Resonance Line in IUE Data
We have used archival International Ultraviolet Explorer high-dispersionSWP spectra to study the B III resonance line at 2065.8 Å in 44early B stars. We find a median boron abundance about half that of solarsystem meteoritic material, consistent with the values found fromprevious studies of boron in early B stars. About one-third of the starsstudied appear to have boron abundances that are a factor of 4 or morelower than this median. Many of these are stars with enhanced nitrogenabundances, confirming the belief that deep envelope mixing can occur inmain-sequence B stars. A few stars with low boron abundances have normalN/C ratios. It is unclear whether all of these can be explained as starswhere mixing depleted the boron but did not go deep enough to bringCN-processed material to the surface or if some stars were actuallyformed with an unusually low boron abundance.
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| Feasibility study of an absolute energy calibration of imaging atmospheric Cherenkov telescopes by starlight
A new method is presented for an absolute energy calibration of imagingatmospheric Cherenkov telescopes as a whole instrument at all relevantwavelengths. For this study the Cherenkov telescope #1 of the HEGRAexperiment was used. The calibration was carried out by detecting thelight of different selected stars during one night. From the data asimple linear correlation was derived between the anode current of theCherenkov camera photomultiplier tubes and the incident photon flux.This result is important for the imaging air Cherenkov technique inseveral aspects: The method enables to determine the response functionof Cherenkov telescopes in the energetic range of Cherenkov lightquickly and reliably. Therefore it can be used as an atmosphericcalorimeter by measuring the absolute integrated flux of Cherenkovphotons. Moreover, the signal of a point run can be predicted and asimulation of the apparatus response can be carried out more reliably.The High Energy Gamma Ray Astronomy experiment is operated on La Palma(Canary Island) by the HEGRA collaboration formed by the University ofHamburg, Max-Planck Institut für Kernphysik, Heidelberg, Universityof Kiel, University of Madrid, Max-Planck Institut für Physik,Munich, University of Wuppertal and the Yerevan Physics Institute.
| A Second Catalog of Orbiting Astronomical Observatory 2 Filter Photometry: Ultraviolet Photometry of 614 Stars
Ultraviolet photometry from the Wisconsin Experiment Package on theOrbiting Astronomical Observatory 2 (OAO 2) is presented for 614 stars.Previously unpublished magnitudes from 12 filter bandpasses withwavelengths ranging from 1330 to 4250 Å have been placed on thewhite dwarf model atmosphere absolute flux scale. The fluxes wereconverted to magnitudes using V=0 for F(V)=3.46x10^-9 ergs cm^-2 s^-1Å^-1, or m_lambda=-2.5logF_lambda-21.15. This second catalogeffectively doubles the amount of OAO 2 photometry available in theliterature and includes many objects too bright to be observed withmodern space observatories.
| Search for forced oscillations in binaries. III. Improved elements and the detection of line-profile variability of the B4V + A6V: system AR Cassiopeiae
An analysis of a new and extensive set of spectroscopic observations ofthe early-type binary system {AR Cas} , based also on spectraldisentangling, has led to the discovery of the spectrum of the secondarystar and of line-profile variations of the B4V primary star. A revisedspectroscopic orbit based on these and published data is presented. Wealso present new photometric data, which have allowed us to improve thesolution of the light curve and demonstrate the presence of apsidalmotion. Determination of the basic physical parameters of the binary hasallowed us to conclude that the system combines the main-sequenceprimary with an A6V: secondary, possibly an Am star. The consistency ofour model of {AR Cas} is documented by a comparison of model atmosphereflux profiles with the profiles recovered from the spectraldisentangling. Analysis of the He i 667.8 nm line indicates that lineprofile variability is present, and that these variations may beperiodic.
| Elemental abundance analyses with DAO spectrograms - XIX. The superficially normal B stars zeta Draconis, epsilon Lyrae, 8 Cygni and 22 Cygni
Elemental abundances of the superficially normal early and middle Bstars zeta Dra, epsilon Lyr, 8 Cyg and 22 Cyg are derived, consistentwith previous studies in this series, using spectrograms obtained withReticon and CCD detectors. Almost all of the derived metal abundancesare found to be solar within the errors of the analysis. However, theHe/H ratios are slightly greater than solar.
| A Search for Star Clusters from the HIPPARCOS Data
We present results of a search for nearby star clusters and associationsusing Hipparcos Catalogue data, restricting the sample to stars withparallaxes above 2 mas (d <~ 500 pc). Two new OB associations havebeen identified in the Carina-Vela and Cepheus-Cygnus-Lyra-Vulpecularegions. A very probable new open cluster has been discovered in Carina.The cluster, a Car, named after its brightest member, is young (60 Myr)and nearby (d = 132 pc). However, only seven bona fide members can bedrawn from the Hipparcos data. We report a detection of nine opencluster candidates in the distance range of 150 to 400 pc, and sixpossible associations almost all located within the Gould belt, althoughslightly older than the known nearby associations. In all cases, wepresent Yale theoretical isochrone fits to the color-magnitude diagrams,which indicate a moderate spread of ages between 60 to 200 Myr.Evidently, these young open cluster and association candidates arerelated to the overall distribution of young OB and A-type stars in thesolar neighborhood.
| 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
| 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
| Properties and nature of Be stars. 17. V360 Lac = HD 216200 is a B3e + F9IV: binary.
An analysis of an extensive collection of photometric and spectroscopicobservations of the little studied bright Be star V360 Lac lead to thefollowing main conclusions: (1) V360 Lac is a binary system consistingof a B3e primary and a F9IV secondary which probably fills the Rochelobe and losses mass towards the primary. Radial-velocity curves of bothcomponents were obtained. (2) The light variations arise fromsuperposition of variations on at least three time scales: phase-lockedorbital brightness and colour changes with two minima; sinusoidalvariation with a 322.24^d^ period and low-amplitude rapid changes with apossible period of 1.6738^d^. (3) A tentative solution of the B and Vlight curves which assumes the semi-detached configuration and presenceof a disk around the primary, combined with the orbital solution, leadsto preliminary basic physical elements of the system which areconsistent with the radiative properties of the binary components.
| The binary system V380 Cyg: Orbital elements, component parameters, and helium abundances
Not Available
| The ROSAT all-sky survey catalogue of optically bright OB-type stars.
For the detailed statistical analysis of the X-ray emission of hot starswe selected all stars of spectral type O and B listed in the Yale BrightStar Catalogue and searched for them in the ROSAT All-Sky Survey. Inthis paper we describe the selection and preparation of the data andpresent a compilation of the derived X-ray data for a complete sample ofbright OB stars.
| 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.
| Jet-like structures in β Lyrae. Results of optical interferometry, spectroscopy and photometry.
A preliminary analysis of an extensive collection of interferometric,spectroscopic and photometric observations of the bright Be star βLyr lead to the following main conclusions: (1) The bulk of the Hαand He I 6678 emission seems to originate in jets of materialperpendicular to the orbital plane of the binary. The jets areassociated with the more massive component of the binary (star 1) andprobably emanate from the `hot spot' in the disk, i.e. the region ofinteraction of the gas stream flowing from the Roche-lobe filling B6-8IIcomponent (star 2) toward star 1. Some contribution to the emission alsocomes from a region located between the two stars (the gas stream andthe `hot spot') and from the `pseudoatmosphere' of the accretion diskaround star 1. (2) The 282-d cyclic variation of the light curve ofβ Lyr is confirmed on the basis of 2852 homogenized V-bandobservations covering an interval of 36yrs. We find, however, that theamplitude and phase of these variations vary with the orbital phase: thelong-term modulation of the light curve almost disappears near orbitalphases 0.25P and 0.50P (elongation and secondary eclipse). (3)Pronounced line-profile variations of the Hα and He I 6678 lineson a time scale shorter than one orbital period were clearly detected.They may be periodic, with a period near 4.70-4.75d, and thisperiodicity may be related to the 282-d change via the orbital period.
| 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.
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Dades d'Observació i Astrometria
| Constel·lació: | Lyra |
| Ascensió Recta: | 19h13m45.50s |
| Declinació: | +39°08'46.0" |
| Magnitud Aparent: | 4.39 |
| Distancia: | 319.489 parsecs |
| Moviment propi RA: | -1.9 |
| Moviment propi Dec: | -0.7 |
| B-T magnitude: | 4.203 |
| V-T magnitude: | 4.373 |
Catàlegs i designacions:
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