Basic structural planes for Mod-A described by Eqs. (25)–(30). In this particular case the effect of the relative kinetic energy of the incoming object is not included (λ = 0), while the luminosity is simply proportional to the mass via the parameter η and the luminosity effects are neglected (θ = 1). The parameters η and ϵ are randomly varied in the intervals, 0.1 ≤ η ≤ 1.0 and 0.1 ≤ ϵ ≤ 1.0, and finally each parameter is summed up N times. In each panel there are four groups of lines. They correspond to the different infall models with mass M_G from which the initial seeds are taken: (from left to right) M_G = 10⁶, 10⁸, 10¹⁰, 10¹² M_⊙. Furthermore, in each group there are six dotted lines of different colours according to the age (i.e. redshift) at which the seeds are taken. The colour-coding is as follows: blue (z = 4), green (z = 3), yellow (z = 2), coral (z = 1), magenta (z = 0.5), and black (z = 0). All data for the seeds are listed in Table 2. Left panel: I_e vs R_e plane. Middle panel: L_V vs σ plane. The dashed line is the best fit limited to the models in four small clouds. Right panel: R_e vs M_s plane. The filled circles are the original seed data.