Possible location of an additional fifth planet in the HD 141399 system. The stability of an Earth-mass planet is analyzed for various semi-major axes versus eccentricity (top) or mean anomaly (bottom). All the angles of the putative planet are set to 0° (except for the mean anomaly in the bottom panel), and in the bottom panel its eccentricity is 0. As in Fig. 13, the color scale corresponds to D values between −6 and 2. The stable zones where additional planets can be found are the dark blue regions.