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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.
| The photometric study of an early-type reverse Algol system - V1425 Cygni
New UBV observations of V1425 Cyg were obtained, showing that the systemconsists of two B-type components exhibiting Beta Lyrae-type lightcurves. An improved orbital period of 1.2523879 for the system isdetermined. Preliminary photometric parameters for a Delta V light curveare derived and photometric analyses are made. The mass ratio of thesystem is derived from a q-search procedure. Two almost identicalsolutions wth similar q are obtained: one with a detached configuration,where the hot component is only slightly detached from the criticalsurface, and the other with a semidetached configuration, where the hotcomponent is just contacting the critical surface.
| Photoelectric photometry of the eclipsing binary V1425 Cygni
Photoelectric differential B and V magnitudes of the eclipsing binaryV1425 Cygni are presented yielding the complete photoelectric lightcurve of this relatively bright system. The improved light elements arecalculated using the least-squares method.
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Osservazione e dati astrometrici
| Costellazione: | Cigno |
| Ascensione retta: | 21h10m58.46s |
| Declinazione: | +55°16'24.8" |
| Magnitudine apparente: | 8.713 |
| Distanza: | 480.769 parsec |
| Moto proprio RA: | 1.1 |
| Moto proprio Dec: | 2.7 |
| B-T magnitude: | 8.739 |
| V-T magnitude: | 8.716 |
Cataloghi e designazioni:
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