Left: recovered albedo and relative error bars as a function of the number of stellar rotations for five different rotators, with P_* = 7, 11, 19, 23, and 26 days. Right: errors of the albedo as a function of the number of stellar rotation observed, for the five rotators with P_* = 7, 11, 19, 23, and 26 days. The input stellar properties are reported in Table 3, while the planetary properties are listed in Table 7. The activity pattern is the one of Table 6. The initial albedo is 0.3.