The true stellar parameters of the Kepler target list

Using population synthesis tools we create a synthetic Kepler Input Catalogue (KIC) and subject it to the Kepler Stellar Classification Program (SCP) method for determining stellar parameters such as the effective temperature Teff and surface gravity g. We achieve a satisfactory match between the synthetic KIC and the real KIC in the log g versus log Teff diagram, while there is a significant difference between the actual physical stellar parameters and those derived by the SCP of the stars in the synthetic sample. We find a median difference Teff =+500 K and∼ log g=−0.2 dex for main-sequence (MS) stars, and∼ Teff =+50 K and log g = −0.5 dex for giants, although there is a large variation across parameter space. For a MS star the median difference in g would equate to a ∼3 per cent increase in stellar radius and a consequent ∼3 per cent overestimate of the radius for any transiting exoplanet. We find no significant difference between Teff and log g for single stars and the primary star in a binary system. We also re-created the Kepler target selection method and found that the binary fraction is unchanged by the target selection. Binaries are selected in similar proportions to single star systems; the fraction of MS dwarfs in the sample increases from about 75 to 80 per cent, and the giant star fraction decreases from 25 to 20 per cent.