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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
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| 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.
| Really Cool Stars at the Galactic Center
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....112.1988B&db_key=AST
| SANTIAGO 91, a right ascension catalogue of 3387 stars (equinox J2000).
The positions in right ascension of 3387 stars belonging to the Santiago67 Catalogue, observed with the Repsold Meridian Circle at Cerro Calan,National Astronomical Observatory, during the period 1989 to 1994, aregiven. The average mean square error of a position, for the wholeCatalogue, is +/-0.009 s. The mean epoch of the catalogue is 1991.84.
| Galactic bulge M giants. IV - 0.5-2.5 micron spectrophotometry and abundances for stars in Baade's Window
Spectrophotometric observations of bulge and local M giants from 0.45 to2.5 microns at a resolution of about 1000 are presented. From ananalysis of strong atomic lines of Na I and Ca I in the K band, a meanmetallicity of the M giants in Baade's Window is derived. It isdemonstrated that J-K is a good temperature indicator for both the fieldand bulge nonvariable M giants, and that the relationship between thetwo quantities is the same for both types of stars. In addition, thereis no difference in the surface gravity between bulge and field giantsof the same J-K color (i.e., temperature). A major difference in theoverall spectral energy distributions of bulge and local M giants isthat the classical H-band bump attributed to the opacity minimum of theH(-) ion near 1.6 microns is considerably reduced in many of the bulgestars.
| A survey for infrared excesses among high galactic latitude SAO stars
This project involves extending the previous analysis of infraredexcesses among a volume-limited sample of 134 nearby A-K main-sequencestars to a magnitude-limited sample of stars, culled from the SAOCatalog, with excesses determined from the IRAS Point Source Catalogflux density ratios. This new sample includes 5706 B-M type stars, 379of which have infrared excesses. The objective involved use of astatistically complete survey of objects in a standard catalog in orderto assess the frequency with which different physical processes canaffect the infrared output of stars. These processes include, but arenot limited to, orbiting cold particle clouds and the onset of rapidmass loss. It is concluded that cold disks are consistent with theinfrared excesses found among A-G dwarfs and G-K giants in the sample.
| M giants in Baade's window - Infrared colors, luminosities, and implications for the stellar content of E and S0 galaxies
In this paper, 1-10 micron photometric observations of M giants inBaade's window are presented and interpreted. When compared to solarneighborhood M giants, it is found that: (1) bulge giants at the samespectral type have bluer JHK colors but stronger CO indices; (2) thenearly dispersionless H-H, H-K relation for the bulge giants lies on theopposite side of the mean field giant relation from that for globularcluster stars; and (3) bulge M giants are up to two magnitudes fainterthan field giants of the same spectral type, and their luminosityfunction drops precipitously for M(bol) brighter than -4.2. It is arguedthat the near-infrared energy distribution of the bulge giants isstrongly affected by molecular blanketing, particularly from H2O.Long-period variables have infrared colors and indices which give themphotometric properties distinct form all other M giants in Baade'swindow. The observed characteristics of the bulge M giants areconsistent with their being representatives of a population with ametallicity considerably in excess of solar.
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Osservazione e dati astrometrici
| Costellazione: | Idra |
| Ascensione retta: | 12h03m38.77s |
| Declinazione: | -32°24'39.2" |
| Magnitudine apparente: | 9.318 |
| Moto proprio RA: | -3 |
| Moto proprio Dec: | -0.1 |
| B-T magnitude: | 11.451 |
| V-T magnitude: | 9.495 |
Cataloghi e designazioni:
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