Towards the absolute planes: a new calibration of the bolometric corrections and temperature scales for Population II giants

We present new determinations of bolometric corrections and effective temperature scales as a function of infrared optical colours, using a large data base of photometric observations of about 6500 Population II giants in Galactic globular clusters (GGCs), covering a wide range in metallicity (−2.0 < [Fe/H] < 0.0). New relations for BCK versus (V − K) , (J − K) and BCV versus (B − V), (V − I), (V − J), and new calibrations for Teff, using both an empirical relation and model atmospheres, are provided. Moreover, an empirical relation to derive the R parameter of the infrared flux method as a function of the stellar temperature is also presented.