Distributions of the inferred metallicities for a synthetic planet (R = 1 R_J and M = 1 M_J) at an age of 0.1 (top row), 3 (middle row), and 8 Gyr (bottom row). The panels in each row show the probability densities for decreasing stellar age uncertainties: r_τ = 50% (left column), 25% (middle column), and 10% (right column). The lines show the probability densities for low stellar irradiation, and the filled curves for high irradiation (F_* = 10⁵ and 10⁸ erg cm⁻² s⁻¹, respectively) Normal and bold font weights correspond to the low and high irradiation models.