Effect of position of stellar active region on M dwarf stars. Panels a–d represent the S/N when the active region is in different positions. The upper panels represent the Earth-size active region with temperatures of 1000 and 10 000 K, for spot and flare, respectively. The bottom panels represent the Jupiter-size active region of spots and flares. Points A, B, and C in panel a represent the position chosen to plot in Fig. 10.