Stacked histogram displaying the distributions of orbital separations Δ (in units of mutual Hill radii) of all 125 pairs of adjacent planets in the mass catalogue shown for each planet multiplicity: systems with three (magenta), four (green), five (blue), and six or seven (red) detected planets. The separations tend to be smaller in high-multiplicity systems. The planets TOI-561 b and c have the largest mutual separation of Δ = 75. The uppercase letters at the top mark the values of all the adjacent planet pairs in the Solar System (Sect. 6).