The thin/thick separation histogram after subtracting the separation curve based on HARPS data (top). [Ti/Fe] against [Fe/H] for the metal-poor stars (bottom). The black dashed line indicates the separation between the thin- and thick disks. The blue crosses represent Kepler planet-hosting candidates. The red squares refer to the Jovian hosts and green triangles refer to the stars exclusively hosting Neptunians and super-Earths detected by HARPS. The black dots refer to the stars without a planetary companion.