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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
| A catalogue of M type stars
The catalogue of 2116 M type and 17 other type stars, carbon stars, Stype stars, and Wolf-Rayet stars, is prepared for the galactic centerregion between 1 = 351 and 1 deg, and between b = -2 and +2 deg. Thecompleteness of the survey down to the limiting magnitude for detectableM type stars is about 90 percent for early (M2-M4) subclasses, and 99percent for intermediate (M5-M6) and late (M6.5-M8) subclasses. Thespectral classification of the M type stars detected is made accordingto the Case system. The accuracy of the positional data for each star iswithin 1.5 sec of arc. Apparent magnitudes in the I and R bands arepresented with an accuracy of + or - 0.3 mag. The limiting magnitude isabout 12.0 in the I band for early M type subclasses and about 12.5 forboth intermediate and late type subclasses. It is suggested that thecatalogue is useful for statistical studies of the galactic structureand further studies on the properties of the stars.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Akrep |
| Sað Açýklýk: | 17h24m43.07s |
| Yükselim: | -36°27'34.2" |
| Görünürdeki Parlaklýk: | 8.213 |
| Uzaklýk: | 456.621 parsek |
| özdevim Sað Açýklýk: | -2.4 |
| özdevim Yükselim: | -8.3 |
| B-T magnitude: | 10.598 |
| V-T magnitude: | 8.41 |
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