Difference in the travel time (Δt_trav) as a function of the clump’s orbital period difference ($\mathrm{\Delta }{P}_{\mathrm{orb}}^{\mathrm{cl}}$) for planets in various conditions. The upper panels show the cases of Fe planets for P_orb = 238 days (panel a) and P_orb = 398 days (panel b). The middle panels show the cases of MgSiO₃ planets for P_orb = 238 days (panel c) and P_orb = 398 days (panel d). The lower panels show the cases of two-layer planets for P_orb = 238 days (panel e) and P_orb = 398 days (panel f). Note that the endpoint of each line corresponds to $\mathrm{\Delta }{P}_{\mathrm{orb},\mathrm{up}}^{\mathrm{cl}}$ and Δt_trav, up.