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Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
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| The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotation
The MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars.
| Polarization measurements of 313 nearby stars
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| The Binary System X Ophiuchi.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959ApJ...130..611F&db_key=AST
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Osservazione e dati astrometrici
| Costellazione: | Ofiuco |
| Ascensione retta: | 18h40m22.61s |
| Declinazione: | +08°52'06.4" |
| Magnitudine apparente: | 6.931 |
| Distanza: | 1086.957 parsec |
| Moto proprio RA: | -4.7 |
| Moto proprio Dec: | -7.7 |
| B-T magnitude: | 7.2 |
| V-T magnitude: | 6.954 |
Cataloghi e designazioni:
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