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UBV absolute CCD photometry and differential astrometry of a sample of visual double stars with A-type primaries
We present V magnitudes, (B-V) and (U-B) colours of the components of111 visual double stars and their relative position measurements rho andtheta . The primaries are of spectral class A; the angular separation isin the 2farcs5 -8arcsec range. The observations were made at the 61-cmreflector of University of Toronto Southern Observatory, Chile. Theobtained photometric results are of a moderate quality for absolutevalues (0.04() m (mag) in V and about 0.02() m in the (B-V) and (U-B)colour indices) and more precise in Delta V and Delta (U-B), Delta (B-V)(0.023() m and 0.015() m, respectively). We find that about 60% ofsecondaries are also of spectral type A; 56% of pairs have Delta (B-V)less than 0.1() m. The two-colour diagram reveals significant offset ofobjects from the curve of unreddened Main Sequence stars. Acomprehensive survey of stars in the close vicinity to the objects isalso presented. The final astrometric accuracy of ~ 0farcs01 in rho and0fdg1 in theta provides additional measurements for study of relativemotion of the components. Based on observations made at University ofToronto Southern Observatory, Las Campanas, Chile. Tables\arabic{tabptm}--\arabic{tabast} are only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html
| A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
| Fast photoelectric photometry of the nova-like variable TT Ari
Rapid photoelectric photometry (sampling time 3s) of the nova-likecataclysmic variable TT Ari has been carried out on three nights(November 22, 23, 24, 1978). Quasi-periodic fluctuations (time scalegreater than or equal to 6 min) and substantial rapid flickering (up to0.02 Hz) are superimposed on an almost sinusoidal light-curve. Duringtwo nights oscillatory events, with periods of approximately 40s, andlasting for about 1500s, have been detected. Inhomogeneities orinstabilities in the accretion disk may be responsible for theproperties of these short periodic oscillations.
| Photographic measures of double stars. II
Measures are presented for 302 double stars photographed on 657 plateswith the 36-in. Lick refractor in the period between 1945 and 1962. Thedata provided include the observing epochs, the rectangular coordinatesof the secondary components with reference to the respective primaries,the mean errors of a single measurement, the computed mean errors, thedouble-star separations, and the position angles both for the observingepoch and reduced to the equator of 2000. An additional 561 unmeasuredplates of acceptable quality obtained between 1948 and 1960 are listed.
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| Takýmyýldýz: | Koc |
| Sað Açýklýk: | 02h07m34.48s |
| Yükselim: | +15°35'23.8" |
| Görünürdeki Parlaklýk: | 8.716 |
| Uzaklýk: | 373.134 parsek |
| özdevim Sað Açýklýk: | 17.2 |
| özdevim Yükselim: | 1.6 |
| B-T magnitude: | 8.868 |
| V-T magnitude: | 8.729 |
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