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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
| Evolution of the symbiotic binary system AG Pegasi - The slowest classical nova eruption ever recorded
We present an analysis of new and existing photometric and spectroscopicobservations of the ongoing eruption in the symbiotic star AG Pegasi,showing that this binary has evolved considerably since the turn of thecentury. Recent dramatic changes in both the UV continuum and the windfrom the hot component allow a more detailed analysis than in previouspapers. AG Peg is composed of a normal M3 giant and a hot, compact starembedded in a dense, ionized nebula. The hot component powers theactivity observed in this system, including a dense wind and aphotoionized region within the outer atmosphere of the red giant. Thehot component contracted in radius at roughly constant luminosity from1850 to 1985. Its bolometric luminosity declined by a factor of about 4during the past 5 yr. Both the mass loss rate from the hot component andthe emission activity decreased in step with the hot component's totalluminosity, while photospheric radiation from the red giant companionremained essentially constant.
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| Takýmyýldýz: | Kanatli At |
| Sað Açýklýk: | 21h51m51.91s |
| Yükselim: | +11°05'28.5" |
| Görünürdeki Parlaklýk: | 6.653 |
| Uzaklýk: | 71.633 parsek |
| özdevim Sað Açýklýk: | 75.1 |
| özdevim Yükselim: | 25.2 |
| B-T magnitude: | 6.962 |
| V-T magnitude: | 6.679 |
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