2025ApJS..277....6Z

The stellar atmospheric parameters and physical properties of stars in the Kepler Input Catalog (KIC) are of great significance for the study of exoplanets, stellar activity, and asteroseismology. However, despite extensive effort over the past decades, accurate spectroscopic estimates of these parameters are available for only about half of the stars in the full KIC. In our work, by training relationships between photometric colors and spectroscopic stellar parameters from Gaia DR3, the Kepler-INT Survey, Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR10, and Galactic Evolution Experiment at Apache Point Observatory DR17, we have obtained atmospheric parameter estimates for over 195,000 stars, accounting for 97% of the total sample of KIC stars. We obtain 1σ uncertainties of 0.1 dex on metallicity [Fe/H], 100 K on effective temperature T_eff, and 0.2 dex on surface gravity log g. In addition, based on these atmospheric parameters, we estimated the ages, masses, radii, and surface gravities of these stars using the commonly adopted isochrone-fitting approach. External comparisons indicate that the resulting precision for turnoff stars is 20% in age; for dwarf stars, it is 0.07 M_⊙ in mass, 0.05 R_⊙ in radius, and 0.12 dex in surface gravity; and for giant stars, it is 0.14 M_⊙ in mass, 0.73 R_⊙ in radius, and 0.11 dex in surface gravity.