Distribution of stellar rotation periods (left) and orbital periods (right). The P_rot distribution from the MMA14 study is shown in violet. The gray bars correspond to the distributions obtained with the unbiased MMA13 sample. The ESPEM distributions with B_p = 0, 1, 10 G are shownin red, light blue and dark blue respectively. The calculation of the error bars for the synthetic distributions is presented in Appendix A.