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Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| Radial-velocity measurements. V - Ground support of the HIPPARCOS satellite observation program
The paper presents data on 1070 radial velocity measurements of starsdistributed in 39 fields measuring 4 deg x 4 deg. The PPO series ofFehrenbach et al. (1987) and Duflot et al. (1990) is continued using theFehrenbach objective prism method.
| Radial velocity measurements. I - Ground-based observations of the program stars for the HIPPARCOS satellite
The radial velocities of 272 stars brighter than m(pg) = 8.5 aredetermined by digital microphotometric measurement of plates obtainedwith dispersion 80 A/mm using the Marly slit spectrograph on the 120-cmtelescope of the Observatoire de Haute Provence. The objects wereselected as probable members of the input catalog for the ESA Hipparcosastrometric satellite. The measurement techniques and data-reductionprocedures are described in detail, and the results are presented inextensive tables and graphs and briefly characterized.
| Calcium in the atmospheres of peculiar stars
Data on the calcium content in the atmospheres of peculiar stars,obtained with model atmospheres and from literature sources, areanalyzed. The Ca I and Ca II spectra in Ap stars are studied. It isshown that the equivalent widths of Ca II K lines in the spectra of Apstars correspond on the average to their color indices B - V, although alarger scatter is observed than for normal stars. The conclusion thatthe calcium content in the atmospheres of Ap stars is normal on theaverage is drawn on the basis of an analysis of the effectivetemperatures used to find the calcium content, the methods ofdetermining the content, and the accuracy in measuring the equivalentwidths of Ca I and Ca II lines. The strengthening and weakening of theintensity of the Ca II K line in the spectra of peculiar stars are mostlikely explained by the difference in the structures of the atmospheresof Ap stars from normal.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Kahraman |
| Sað Açýklýk: | 02h57m54.09s |
| Yükselim: | +46°39'40.4" |
| Görünürdeki Parlaklýk: | 7.587 |
| Uzaklýk: | 129.199 parsek |
| özdevim Sað Açýklýk: | -32.9 |
| özdevim Yükselim: | -20.4 |
| B-T magnitude: | 7.794 |
| V-T magnitude: | 7.605 |
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