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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
| UBVRI photoelectric photometry of nearby stars. II
A second set of UBVRI photometry results for nearby stars of Gliese's(1969) catalog and its supplements, including in this case some multiplesystems, are presented. Most of the observations were carried outbetween July 1984 and December 1985 at Calar Alto with the 1.23-m CentroAstronomico Hispano-Aleman telescope and the 1.52-m ObservatorioAstronomico Nacional telescope. The number of observations of programand standard stars for the six runs and the final results for 60 starsare presented.
| Dwarf K and M stars of high proper motion found in a hemispheric survey
A recently completed visual/red spectral region objective-prism surveyof more than half the sky found some 2200 dwarf K and M stars ofnegligible proper motion (Stephenson, 1986). The present paper adds the1800-odd spectroscopically identified dwarfs that did prove to havesignificant proper motions. About half of these had previous spectralclassifications of some sort, especially by Vyssotsky (1952, 1956). Forthe great majority, the present coordinates are more accurate thanprevious data. The paper includes about 50 stars with unpublishedparallaxes, likely to have parallaxes of 0.05 arcsec or more. Combiningthe present data with the first paper suggests that the number oflow-proper-motion stars in that paper was not unreasonable.
| Dwarf K and M stars dicovered on objective-prism plates.
Abstract image available at:http://adsabs.harvard.edu/abs/1975AJ.....80..972S
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Pozíciós és asztrometriai adatok
| Csillagkép: | Sas |
| Rektaszcenzió: | 20h41m40.69s |
| Deklináció: | -05°29'34.3" |
| Vizuális fényesség: | 10.681 |
| Távolság: | 27.91 parszek |
| RA sajátmozgás: | 74.4 |
| Dec sajátmozgás: | 64.1 |
| B-T magnitude: | 12.141 |
| V-T magnitude: | 10.802 |
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