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The eclipsing double-lined binaries V883Cen and ? Mus
We derive the orbital period and monitor in detail the eclipses of twodeep-southern double-lined eclipsing binaries of considerable interest.We present new uvby photometry over more than 100 nights for V883Cen,scan for the first time the eclipses of ? Mus and analyse the datafor these two systems together with earlier published photometry. Wealso add information from high-dispersion spectra.V883Cen consists of two sharp-lined, mid-B-type stars in an orbit of35.44733 d. The slower rotating component, Prot = 55.215 d,is a chemically peculiar star of the type He-weak SrTi that is partiallyeclipsed by its slightly more massive companion. Owing to the higheccentricity of the orbit and its orientation, only one eclipse occurs.The orbital period of ? Mus is 57.5 h, rather than the 20 d quotedup to the present in the literature. That close binary, consisting oftwo late-B-type stars, shows identical partial eclipses. Interest in theclose binary is triggered by the pre-main-sequence companion at 2.7arcsec. HD118978, one of the comparison stars used for V883Cen, isidentified as a new variable. This fast-rotating B9 (sub)giant belongspresumably to the class of slowly pulsating B-type stars.Based on observations obtained at the European Southern Observatory(ESO), La Silla, Chile, and at the South African AstronomicalObservatory (SAAO), Sutherland, South Africa.E-mail: herman@oma.be ‡Research Director, Belgian Fund for Scientific Research (FWO).
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association
B- and A-type stars in and near the Sco-Cen OB association areinvestigated with UBV and H-beta photometry to acquire data relevant tothe luminosity function of Sco-Cen. The measurements generally consistof two 10-s integrations of U, B, V, (W, N) filters, and theobservations are corrected iteratively for atmospheric extinction andinstrumental response. The data presented give the mean V magnitude,mean B-V, mean U-B, and the estimated uncertainties for these values.The catalog provides a homogeneous catalog of data for a large fieldwith stellar objects delineating membership to the association Sco-Cenand that affect the luminosity function of the aggregate.
| The local system of early type stars - Spatial extent and kinematics
Published uvby and H-beta photometric data and proper motions arecompiled and analyzed to characterize the structure and kinematics ofthe bright early-type O-A0 stars in the solar vicinity, with a focus onthe Gould belt. The selection and calibration techniques are explained,and the data are presented in extensive tables and graphs and discussedin detail. The Gould belt stars of age less than 20 Myr are shown togive belt inclination 19 deg to the Galactic plane and node-lineorientation in the direction of Galactic rotation, while the symmetricaldistribution about the Galactic plane and kinematic properties (purecircular differential rotation) of the belt stars over 60 Myr oldresemble those of fainter nonbelt stars of all ages. The unresolveddiscrepancy between the expansion observed in the youngest nearby starsand the predictions of simple models of expansion from a point isattributed to the inhomogeneous distribution of interstellar matter.
| Radial velocities for early type stars in six galactic regions
Coudespectroscopy has been carried out for 353 stars of spectral typesB0-A0 and V magnitudes between 6.5 and 10.8 m, selected in six regions(three northern and three southern) close to the galactic plane at thegalactic longitudes 135, 175, 315 and 350 deg. The radial velocitieswere obtained by cross-correlating each spectrogram with a referencespectrogram giving an internal error of 1.4 km/s.
| Search for Beta Cephei stars south of declination -20 deg. II - Photometric and spectrographic observations of early B giants and subgiants - Winter objects
Results of the second part of a program begun in 1975 (Jerzykiewicz andSterken, 1977) are presented. Out of 39 Beta Cephei candidates observedphotometrically, seven turned out to vary with the b ranges exceeding0.020 m, while 21 have been found constant to within 0.010 m or better.For the 56 comparison stars these numbers are 6 and 25, respectively.From spectrographic observations one of the candidates, HD 129557 = HR5488 (B2 III), iis found to be a Beta Cephei variable with a period of0.135 d and the 2 K amplitude of 18.4 km/s. A comparison of the resultsof this program with other recent photometric searches for Beta Cepheivariables shows good agreement in most cases. There are severaldiscrepant stars, however. These are discussed in some detail. Aconclusion emerges that in the low temperature extension of the BetaCephei region, if such an extension exists at all, on-and-off typepulsations occur.
| Four-colour and H-beta photometry for early type stars in three southern galactic regions
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...41...85L&db_key=AST
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Osservazione e dati astrometrici
| Costellazione: | Centauro |
| Ascensione retta: | 13h47m57.81s |
| Declinazione: | -55°57'38.2" |
| Magnitudine apparente: | 7.199 |
| Distanza: | 500 parsec |
| Moto proprio RA: | -10.1 |
| Moto proprio Dec: | -4 |
| B-T magnitude: | 7.206 |
| V-T magnitude: | 7.2 |
Cataloghi e designazioni:
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