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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.
| Interstellar polarization at high galactic latitudes from distant stars. VII. A complete map for southern latitudes b < -70°
We present a detailed map of interstellar polarization for the SouthGalactic Pole (b < -70°). The map is based on new polarizationmeasurements of 183 stars of spectral classes from A to K at distancesof up to 500 pc. We use polarization data to investigate thedistribution of dust and to map the Galactic magnetic field at highsouthern Galactic latitudes and make a comparison with the oppositenorthern polar zone. In general, the magnetic field is smoother in thesouth and aligned with the global pattern. There are no extended dustystructures in the south similar to Markkanen's cloud in the north.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Balina |
| Sað Açýklýk: | 01h00m44.30s |
| Yükselim: | -24°16'17.4" |
| Görünürdeki Parlaklýk: | 8.861 |
| Uzaklýk: | 138.889 parsek |
| özdevim Sað Açýklýk: | -16.3 |
| özdevim Yükselim: | 5 |
| B-T magnitude: | 9.305 |
| V-T magnitude: | 8.898 |
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