Fig. 8
From: A generalized framework for the collinear restricted four-body problem with a central dominant mass
Variation of the characteristic roots Λ1,2 for the libration point L1 with μ0 = 0.75 and 0 < μ < 0.125. The condition Λ1 > 0 and Λ2 < 0 indicates a saddle–center configuration, confirming the linear instability of L1.
