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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
| An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
| An update of the ephemeris of V566 Ophiuchi.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989RMxAA..17...39H&db_key=AST
| UVBY H-beta photometry of UV-bright stars
uvby H-beta photometry is presented for 90 stars taken from an earlyversion of the Carnochan and Wilson (1983) catalogue of stars that havevery negative UV colors. Two have definite UV excesses (HD 36629, and HD81307). Four early-B stars have UV colors too positive for their visibleclassification, and beta-indices that indicate higher luminosities thanappear possible on galactic distribution grounds. Six late-B starsappear to have discordant flux distributions for which there are noobvious explanations. It is suggested that the high population ofsubluminous stars derived by Carnochan and Wilson is the product of thestatistical treatment used and the extreme patchiness in theinterstellar absorption, which gives rise to large numbers oflittle-reddened stars.
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