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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.
| Differential Corrections Analysis of the UBVRI Observations of AG Phoenicis
The first photoelectric analysis of the Algol-like system AG Phe basedon U, B, V, R and I light curves and modeled using the Wilson andDevinney approach, is presented. The light curves are defined by 9246individual observations. The components and the orbit appears to bestable. The primary, more massive, more luminous and greater component,eclipsed (total transit) at primary minimum, is detached from its Rochelobe (79%). The secondary nearly fills its Roche lobe (99%) and has atemperature difference of Delta T=-3310 K. Preliminary derived absolutedimensions M_1/Modot=1.42, R_1/Rodot=1.66,L_1/Lodot=7.83, log g_1=4.15 assign normal MS characteristicsand a low degree of evolution to the A8V primary, whileM_2/Mȯ=0.22, R_2/Rodot=0.93, L_2/Lodot=0.29,log g_2=3.84 suggest an evolved K2 sub-giant secondary.
| A photometric orbit for the eclipsing binary AG Phoenicis
In each of the UBV bandpasses about 1760 observations define for thefirst time the photoelectric light variation of the binary system AGPhe. A consistent set of elements is derived in the framework of theclassical model. The system would be a well-detached binary consistingof two normal A9 and K0 main-sequence components.
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| Takýmyýldýz: | Anka |
| Sað Açýklýk: | 00h26m50.39s |
| Yükselim: | -39°33'33.3" |
| Görünürdeki Parlaklýk: | 9.11 |
| özdevim Sað Açýklýk: | 43 |
| özdevim Yükselim: | -2.7 |
| B-T magnitude: | 9.679 |
| V-T magnitude: | 9.157 |
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