Detection sensitivity of ϵ Eri obtained by NACO/L_P as a solid curve and ϵ Eri b are plotted as in Fig. 2, based on the AMES-Cond model with ages of 200, 400, and 800 Myr from left to right. The contours of the secular perturbation are shown for the asymmetric disk with different orbital eccentricities where t_cross = t_age is assumed. Dotted and dashed curves represent contours corresponding to the different orbital eccentricities of a planet around ϵ Eri: 0.01, 0.1, 0.4, and 0.7.