Effective temperature scale and bolometric corrections from 2MASS photometry

Abstract

We present a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 K. By taking into account all possible sources of error we estimate associated uncertainties to better than 1% in effective temperature and in the range 1.0–2.5% in angular semi-diameter for unreddened stars. Comparison of our new temperatures with other determinations extracted from the literature indicates, in general, remarkably good agreement. These results suggest that the effective temperaure scale of FGK stars is currently established with an accuracy better than 0.5%–1%. The application of the method to a sample of 10 999 dwarfs in the Hipparcos catalogue allows us to define temperature and bolometric correction (K band) calibrations as a function of (V − K), [m/H ]a nd logg. Bolometric corrections in the V and K bands as a function of Teff ,[ m/H] and log g are also given. We provide effective temperatures, angular semi-diameters, radii and bolometric corrections in the V and K bands for the 10 999 FGK stars in our sample with the corresponding uncertainties.