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Hipparcos red stars in the HpV_T2 and V I_C systems For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/397/997
| New UBVRI photometry for 900 supergiants A description is presented of the results obtained in connection with asystematic program of supergiant photometry on the Johnson UBVRI system.During the eight years after the start of the program, almost 1000 starshave been observed, about 400 three or more times each. The originalselection of stars used the spectral type catalog of Jaschek et al.(1964) to choose supergiants. Since observations were possible from bothChile and Canada, no declination limits were imposed, and no particularselection criteria were imposed other than to eliminate carbon stars.These are so red as to require enormous extrapolations of thetransformation equations.
| Spectral and Luminosity Classification of the Bright Sequence Stars in the C Regions. Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJ...121...32N&db_key=AST
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Osservazione e dati astrometrici
Costellazione: | Leone |
Ascensione retta: | 11h06m33.45s |
Declinazione: | +15°02'16.8" |
Magnitudine apparente: | 8.914 |
Distanza: | 289.017 parsec |
Moto proprio RA: | -10.7 |
Moto proprio Dec: | -5.7 |
B-T magnitude: | 10.797 |
V-T magnitude: | 9.07 |
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