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The 75th Name-List of Variable Stars
We present the next regular Name-List of variable stars containinginformation on 916 variable stars recently designated in the system ofthe General Catalogue of Variable Stars.
| 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
| Variations of AP stars in the Geneva system
The photometric behaviour of 21 Ap stars has been analyzed fromobservations obtained in the Geneva system. Variability has beendetected for 9 Ap stars, as well as for a star which initially was acomparison star. Preliminary values for the periods are presented aswell as an analytical description of the light curves. based onobservations made at the Swiss telescope of the European SouthernObservatory, La Silla, Chile. Complete Table 4 is available inelectronic form at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstract.html and full figures are accessibleon the on-line version of the paper.
| Mesures de vitesses radiales. VII. Accompagnement AU sol DU programme d'observation DU satellite Hipparcos. Radial velocities. VII. Ground based measurements for Hipparcos.
We publish 734 radial velocities of stars distributed in 28 fields of4x4deg. We continue the PPO series (Fehrenbach et al. 1987; Duflot etal. 1990 and 1992), using the Fehrenbach objective prism method.
| Evidence of decay of the magnetic fields of AP stars
Data obtained in the Geneva photometric system (Rufener, 1981) andappropriate calibrations of this system in terms of surface magneticfield and gravity are used to provide, on the basis of 708 field andcluster Ap stars, observational evidence that these stars undergo decayof their magnetic field on an evolutionary timescale. Justifications aregiven for the application of a photometric gravity calibration topeculiar stars. The dependence of the photometrically estimated surfacemagnetic field on gravity is found to differ markedly from availabletheoretical calculations. HgMn stars are found to show the same trend,strengthening the impression that they might be slightly magnetic.He-weak stars do not.
| Catalogue et bibliographie des étoiles A à spectre particulier - Deuxième supplément
Not Available
| Catalogue et bibliographie des étoiles A à spectre particulier
Not Available
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Observation and Astrometry data
| Constellation: | Dauphin |
| Right ascension: | 20h15m42.39s |
| Declination: | +13°50'56.9" |
| Apparent magnitude: | 9.211 |
| Proper motion RA: | -1 |
| Proper motion Dec: | -3.1 |
| B-T magnitude: | 9.249 |
| V-T magnitude: | 9.215 |
Catalogs and designations:
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