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Intensive photometry of southern Wolf-Rayet stars
Results of an intensive photometric campaign on 17 of the brightestsouthern Wolf-Rayet stars are presented. The detection ofmultiperiodicity in two stars, HD 50896 and HD 96548, is reported. It islikely that these periodicities are not coherent but are manifestationsof the quasi-periodic variations seen in a few WR stars. A good exampleof these variations is given by HD 86161. A new eclipsing binary, HD92740, has been discovered; other stars show periodic variations whichcan be explained by phase-dependent scattering of the secondary light asit traverses the Wolf-Rayet wind. An important conclusion of this studyis that not a single example was found of short-period variations whichcan be attributed to pulsation.
| Photometry of southern Wolf-rayet stars.
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| Five-colour photometry of early-type stars in the direction of galactic X-ray sources
The results of five-color (Walraven system) photometry of 551 O- andB-type stars located in 17 fields of a few square degrees aroundgalactic X-ray sources are presented. From a comparison ofreddening-free combinations of color indices with theoretical values,calculated for model atmospheres of Kurucz (1979), effective temperatureand surface gravity for these stars are derived. In addition theirabsolute magnitude are determined by combining these parameters with theresults of evolutionary calculations of massive stars. These effectivetemperatures are in good agreement with the temperature scale ofBohm-Vitense (1981) for stars of luminosity classes II to V. For thesupergiants the effective temperatures are about 40 percent higher. Forstars of luminosity classes III to V the absolute magnitudes agree wellwith the results of independent luminosity calibrations of spectraltypes, but for brighter stars they deviate systematically. Thephotometric data are also used to study the interstellar reddening inthe direction of the X-ray sources.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Guney Ucgeni |
| Sað Açýklýk: | 15h34m14.48s |
| Yükselim: | -60°48'28.6" |
| Görünürdeki Parlaklýk: | 7.172 |
| Uzaklýk: | 122.85 parsek |
| özdevim Sað Açýklýk: | -26.6 |
| özdevim Yükselim: | -37.6 |
| B-T magnitude: | 7.246 |
| V-T magnitude: | 7.179 |
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