Histograms of the predicted change in S2’s argument of peribothron, ω, over the course one orbital period (~16 yr). The shift due to relativity, (Δω)_GR ≈ 11′, has been subtracted from the total; what remains is due to Newtonian perturbations from the field stars. Each histogram was constructed from integrations of 100 random realizations of the same initial model, with field-star mass m = 10 M_⊙, and four different values of the total number: N = 200 (solid/black); N = 100 (dotted/red); N = 50 (dashed/blue); and N = 25 (dot-dashed/green). The average value of the peribothron shift increases with increasing Nm, as predicted by Eq. (11). The reasons for the spread in Δω values are discussed in the text.