The true stellar parameters of the Kepler target list

ISSN： 0035-8711

Source： Monthly Notices of the Royal Astronomical Society, Vol.433, Iss.2, 2013-01, pp. : 1133-1145

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Abstract

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 T_eff and surface gravity g. We achieve a satisfactory match between the synthetic KIC and the real KIC in the logg versus logT_eff 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 T_eff500K andlogg0.2dex for main-sequence (MS) stars, andT_eff50K and logg0.5dex for giants, although there is a large variation across parameter space. For a MS star the median difference in g would equate to a3percent increase in stellar radius and a consequent3percent overestimate of the radius for any transiting exoplanet. We find no significant difference between T_eff and logg 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 80percent, and the giant star fraction decreases from 25 to 20percent.