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New beta Cephei and SPB Stars Discovered in Hipparcos Photometry
We discuss 34 stars for which we detected new frequencies in HipparcosHp magnitudes. 13 of these stars are variables discovered in this paper.For 20 stars, we derive log T_eff and log g from Stromgren or Genevaphotometry.We classify one new beta Cep star, HIP 88352, two new beta Cep suspects,HIP 54753 and 88123, four new SPBs, HIP 1030, 39206, 46192 and 111147,and two SPB suspects, HIP 75787 and 98778. We find the last star to betriply-periodic and we show that the frequencies detected in Hpmagnitudes are present in the photoelectric observations of Hill etal(1976).Finally, we discover the hottest variable of the SPB type, namely, HIP1030.
| 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
| Radial velocity measurements. IV - Ground-based accompaniment to the HIPPARCOS observation program
The paper presents 396 radial velocities of stars distributed in 19fields of 4 x 4 degrees. The study employs the Fehrenbach objectiveprism method and the same measuring technique used in a previous paper(Fehrenbach et al., 1987).
| The nature of the visual companions of AP and AM stars
The stars in 43 visual multiples with Ap or Am primaries have beenclassified, and the fraction of systems that have Ap or Am secondariesis counted. The numbers of Ap secondaries are too few to be informative,but an apparent excess of Am secondaries is found. That result isunderstandable in terms of the (published) moderate correlation inrotational velocities between components in visual multiples. But invarious open clusters, the variations in frequencies of Ap and Am starscan be explained probably as statistical fluctuations in small numbersof stars, indicating no tendency for abnormal stars to group togetherfor dimensions larger than those of visual multiples.
| A spectroscopic investigation of visual binaries with B-type primaries.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969AJ.....74.1082M&db_key=AST
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Observation and Astrometry data
| Constellation: | Δράκων |
| Right ascension: | 20h22m54.33s |
| Declination: | +64°10'58.5" |
| Apparent magnitude: | 9.216 |
| Distance: | 617.284 parsecs |
| Proper motion RA: | 11.4 |
| Proper motion Dec: | -8.1 |
| B-T magnitude: | 9.371 |
| V-T magnitude: | 9.229 |
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