Variation in the planetary signal (solid blue line), stellar Poisson noise (dashed blue line), and the S/N (dashed red line) as the baseline length changes. The gray dotted lines indicate the baseline lengths for M-dwarfs (top) and G-type (bottom) stars at which the signals for detecting habitable planets or the S/N are at maximum. Note: the total exposure time for a M dwarf is 5000 s, compared to 20 000 s for a G dwarf.