Top: distribution of tangential velocities of MHO features (in 10 km s^-1 bins); middle: the distribution of μ_αcosδ (in 30 mas yr^-1 bins); bottom: the distribution of μ_δ (in 30 mas yr^-1 bins). The open columns are for all PM measurements of MHO features in Ophiuchus and the gray filled columns are for the PM measurements with status of “0” (reliable measurements) of MHO features. The red dashed line in top panel shows the fitting with the exponential function for the MHO features with the reliable tangential velocities greater than 40 km s^-1.