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Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| Secondary UVBY standards in the Harvard E-regions
Photoelectric uvby photometry for 201 stars which are already UBV (RI)cstandards is presented. The photoelectric data are closely tied to theCousins uvby standards and the stars should be suitable for use asfainter (7-11 mag) secondary standards.
| Large and kinematically unbiased samples of G and K type stars. I - The dwarfs
Four-color, H-beta, and (R,I) photometry for the little-evolvedmain-sequence stars from the Bright Star Catalogue, South Galactic Pole,Griffin (1971), and Moore-Paddock-Wayman (Moore and Paddock 1950, andWayman 1960) samples are analyzed. The luminosity and heavy-elementabundances for these stars are calculated in terms of the Hyadessupercluster, the Wolf 630 group, the Sirius supercluster, and theKapteyn star group. The data reveal the presence of a metal-abundancedependent discontinuity near M(v) = +7 mag in the photometric parametersof dwarfs. The distributions of the abundances and the space motions ofthe sample stars are discussed.
| Four-colour observations of primary and secondary UVBY standards
Stromgren uvby photometry of primary standards and of the secondarystandards observed by Cousins (1985) in the E regions and by Twarog(1984) near the South Galactic Pole suggests that the Twarog c1 resultsare not on the standard system. Inconsistencies also occur in V and m1but it is not clear from which data these arise. Intercomparisonsdiscussed in this paper and by Eggen (1982, 1984) suggest thatsystematic errors, particularly in m1 and c1, could be widespread inSouthern Hemisphere uvby observations.
| UVBY secondary standards near the South Galactic Pole
uvby photometry of sufficient accuracy to qualify as secondary standarddata is presented for 36 stars of spectral type A5-G5 near the SouthGalactic Pole. The stars range in magnitude from V = 8.4 to 13.5. Twoanomalous stars, one an earlier misidentified and one a variable in V,are discussed.
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | פסל |
| התרוממות ימנית: | 01h09m13.29s |
| סירוב: | -33°12'50.4" |
| גודל גלוי: | 9.798 |
| תנועה נכונה: | 32.9 |
| תנועה נכונה: | -26 |
| B-T magnitude: | 10.515 |
| V-T magnitude: | 9.858 |
קטלוגים וכינוים:
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