Calibration of (B-V)_{0} for MILES stars

The integrated spectral properties of a stellar system bring information from the mixture of stellar populations within the system. The (B-V) colour is one of the observational properties that can help determine the age and metallicity of stellar populations in a star cluster or even in galaxies. We have derived a series of empirical calibrations of the intrinsic colour, (B-V)_{0}, as a function of T_{eff}, [Fe/H] and [α/Fe]. The stellar parameters of MILES stars have been redetermined homogeneously. The calibrations were obtained individually for distinct spectral types (O-B, A, F-G-K and M), which were then further subdivided into as many as five ranges in [Fe/H]. For the M types only, the stars were divided into dwarfs and giants. (B-V)_{0} was measured directly using the MILES fully calibrated stellar spectra (typical error = 0.025 mag). Here, we present just the (B-V)_{0} calibrations for F-G-K types that are split into five [Fe/H] ranges. We find that the error in (B-V)_{0} varies from 0.014-0.022 mag. The next main goal is to compute (B-V)_{0} self-consistently for semi-empirical simple stellar population models based on MILES.