Correlation of the eccentricity of K2-19 b (left panel) and K2-19 c (right panel) with the difference in the longitudes of periastron over the time span covered by the observations for 1000 random draws from the posterior distribution. Samples that circulate are shown in light gray (one random sample is shown in black), those that librate around ϖ_b − ϖ_c = 0° are shown in light blue, and those that librate around ϖ_b − ϖ_c = 180° are shown in light red (one random sample is shown in red). The MAP model, which librates around 0, is shown in blue. The dots, with the same color code, represent the positions at t_ref.