Probability density functions of the location of stars in the U−V plane for different cases and Δ_bin = 1.0 km s^-1. Case A1: the star is located in the centre of a bin and the uncertainty is equal to the average uncertainty of the stars in our sample (σ_U = ⟨ σ_U ⟩ = 1.80 km s^-1 and σ_V = ⟨ σ_V ⟩ = 1.60 km s^-1). Case A2: the star is located close to the edge of a bin and the uncertainty is equal to the average uncertainty of the stars in our sample (σ_U = ⟨ σ_U ⟩ = 1.80 km s^-1 and σ_V = ⟨ σ_V ⟩ = 1.60 km s^-1). Case B1: the star is located in the centre of a bin and the uncertainty is lower than the average uncertainty of the stars in our sample (σ_U = ⟨ σ_U ⟩ = 0.90 km s^-1 and σ_V = ⟨ σ_V ⟩ = 0.80 km s^-1). Case B2: the star is located close to the edge of a bin and the uncertainty is lower than the average uncertainty of the stars in our sample (σ_U = ⟨ σ_U ⟩ = 0.90 km s^-1 and σ_V = ⟨ σ_V ⟩ = 0.80 km s^-1). Numbers at each concentric circle show the probability as a percentage for the star to fall inside the circle.