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Positional reference stars in the Magellanic Clouds
The equatorial coordinates are determined of 926 stars (mainly ofgalactic origin) in the direction of the Magellanic Clouds at the meanepoch T = 1978.4 with an overall accuracy characterized by the meanvalues of the O-C coordinates, Sa = 0.35 arcsec and Sd = 0.38 arcsec,calculated from the coordinates of the Perth reference stars. Thesevalues are larger than the accuracy expected for primary standard stars.They allow the new positions to be considered as those of reliablesecondary standard stars. The published positions correspond to anunquestionable improvement of the quality of the coordinates provided inthe current catalogs. This study represents an 'astrometric step' in thestarting of a 'Durchmusterung' of the Magellanic Clouds organized by deBoer (1988, 1989).
| 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.
| A photoelectric UBV sequence in the region of the wing of the Small Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...33..107J&db_key=AST
| Sir John Herschel's Observations of Stars in the Small Magellanic Cloud
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Osservazione e dati astrometrici
| Costellazione: | Idro |
| Ascensione retta: | 01h35m44.91s |
| Declinazione: | -72°44'22.0" |
| Magnitudine apparente: | 8.92 |
| Distanza: | 371.747 parsec |
| Moto proprio RA: | 7.2 |
| Moto proprio Dec: | 5.3 |
| B-T magnitude: | 10.418 |
| V-T magnitude: | 9.044 |
Cataloghi e designazioni:
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