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The Pul-3 catalogue of 58483 stars in the Tycho-2 system
A catalogue of positions and proper motions of 58483 stars (Pul-3) hasbeen constructed at the Pulkovo observatory. The Pul-3 is based on theresults of measurements of photographic plates with galaxies (Deutsch'splan). All plates were taken using the Pulkovo Normal Astrograph (thefirst epoch is in the 1950s and the second epoch is in the 1970s).The Pul-3 catalogue contains stars of mainly 12 to 16.5 mag in 146fields with galaxies in the declination zone from -5o to+85o. The Tycho-2 has been used as a reference catalogue.The mean epoch of the Pul-3 is 1963.25. The internal positional accuracyof the Pul-3 catalogue at the mean epoch of observations is ±80mas. The accuracy of the proper motions is mostly within ±3mas/yr to ±12 mas/yr. Comparisons of the Pul-3 with Tycho-2 andARIHIP have been done at the mean epoch of the Pul-3. The Pul-3 externalpositional accuracy relative to Tycho-2 is ±150 mas.The catalogue is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/357
| Interstellar and intergalactic gas towards SN 1993J in M 81: A study of optical and 21 CM spectra
We present a study of the interstellar and intergalactic clouds locatedin the direction of the recent supernova 1993J in M81 based on theanalysis of optical and 21 cm spectra obtained during the first nightsafter its discovery. The optical spectra were taken at high spectralresolution (FWHM 4 to 6 km/s) using the 4.2 m William Herschel Telescope(La Palma, Spain), covering the resonance lines of CN, Ca II, Ca I,CH(+), CH, Na I, Li I and K I. We also observed in Ca II a sample offoreground Galactic stars in the field of the supernova. The 21 cmspectra were taken with the 100 m Effelsberg Radiotelescope (beam FWHMapproximately equals 9 min) at the position of SN 1993J and in 6positions around the supernova, at 10 min separation.
| A magnitude limited stellar X-ray survey and the F star X-ray luminosity function
An X-ray survey has been conducted of stars brighter than visualmagnitude 8.5 that have serendipitously fallen into the fields of viewof the Imaging Proportional Counter of the Einstein Observatory. Thesurvey includes 227 separate 1 x 1 deg fields, containing 274 stars witha visual magnitude of no more than 8.5 and covering a wide range ofspectral types and luminosity classes. X-ray emission was detected from33 stars, and upper limits have been determined for the remainder of thesample. F type stars dominate the detected sample, and most of these areshown to be dwarfs. An X-ray luminosity function for dF stars has beendeduced, and reveals that the average 0.2-4.0 keV luminosity of thesestars is around 10 to the 29th erg/sec. Constraints have been placed onthe high luminosity tails and medians of the X-ray luminosity functionsfor other types of stars.
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Osservazione e dati astrometrici
| Costellazione: | Orsa Maggiore |
| Ascensione retta: | 09h54m02.55s |
| Declinazione: | +71°40'53.0" |
| Magnitudine apparente: | 7.752 |
| Distanza: | 266.667 parsec |
| Moto proprio RA: | -12.6 |
| Moto proprio Dec: | -18.2 |
| B-T magnitude: | 7.782 |
| V-T magnitude: | 7.755 |
Cataloghi e designazioni:
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