Metallicity as a function of the effective temperature for stars with Jupiters (red circles), with Neptunes (blue triangles) and comparison sample stars (black crosses). The dotted line represents the approximate lower and upper limits in B − V (B − V = 0.5 and 1.2). The T_eff distributions of all sample stars without planets (black dotted) and stars hosting Jovians (red dashed) and only Neptunians (shaded blue) are presented in the right bottom panel, and the distributions of the stars in the rectangle are shown in the left bottom.