Silhouette plots for our cluster analysis of the posterior distribution of Ω_★ and i_★. Silhouette plots are shown (from top to bottom) for three, four, and five clusters. In each case, the silhouette coefficients are plotted in the left panel, where the silhouette statistic is indicated with a dashed red line. The clusters are shown in λ − i_★ space in the right panels, using the same colour coding as in the corresponding left-hand panel. For more details, see Section 7.1.