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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
| Medium-Resolution Stellar Spectra in the L Band from 2400 to 3000 cm-1 (3.3 to 4.2 Microns)
We present a brief atlas of L-band (3.3-4.2 μm) spectra for 42 starsplus the Sun and a sunspot observed at a resolving power of R~3000. Thiscontribution is intended to supplement our previous K-band, H-band, andJ-band spectral atlases. The L-band data, which cover some or all of the2400 to 3000 cm-1 (3.3-4.2 μm) region, are mainly forluminous late-type stars. In reducing these data, special care has beentaken to remove telluric features, especially water vapor. We identifytemperature- and luminosity-sensitive atomic and molecular indices toaid in the classification of stellar spectra in the L band. The data areavailable electronically.
| Rapidly oscillating M giant stars?
The Hipparcos mission discovered a few dozen M giant stars with periodsP shorter than 10d. Similar stars may be found in other large data basesof new variables (e.g., OGLE). The three possible sources of themagnitude variations - pulsation, starspots and ellipsoidal deformation- are discussed in general terms. The parallaxes and V-I colour indicesare used to calculate radii and temperatures for all M giant variableswith P<100d. Masses are estimated from the positions of the stars ina Hertzsprung-Russell (HR) diagram, using evolutionary tracks. Usingthese data, it is shown that starspots can be ruled out as a variabilitymechanism in almost all cases, and ellipsoidal variations in about halfof the stars. Pulsation in very high-overtone modes appears to be theonly viable explanation for the stars with P<10d. Many of the starsmay be multiperiodic. IRAS data are used to deduce information aboutreddening and circumstellar dust. The apparently low level of mass-loss,as well as the kinematics and the spatial distribution of the stars,indicates that they are from a relatively young (i.e., thin disc) giantstar population.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| Photoelectric photometry of M-type stars
UBVRI photoelectric photometry was obtained for 110 M-type starscontained in the Caltech Two-Micron Survey and the revised AFGL Catalog.Of the 110 stars, 58 have a color index (B-R) greater than or equal to 4mag. A graph is given of (V-R) versus (V-I) for the present stars.
| The dynamical structure of the h+chi Per association.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971A&A....10..414G&db_key=AST
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | קאסיופיאה |
| התרוממות ימנית: | 01h16m47.88s |
| סירוב: | +75°12'02.2" |
| גודל גלוי: | 8.62 |
| מרחק: | 395.257 פארסק |
| תנועה נכונה: | 24.9 |
| תנועה נכונה: | -1.5 |
| B-T magnitude: | 10.528 |
| V-T magnitude: | 8.778 |
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