Planet eccentricity as a function of star-star separation (panel a, left, in au) and of ratio between star-star separation and semi-major axis (panel b, right). The red lines show the predicted mean value p of the beta distributions as a function of the dependent variable, in logarithmic scale. The blue shades around these lines correspond to their 95% HDI. The insets show the corresponding posterior probability distribution of the β₂ parameters, and the vertical green lines mark β₂ = 0. Green triangles mark the mean eccentricities in bins of 1 dex, together with error bars for their formal errors. The dashed red line in panel b shows the result of a generalised model using a quadratic fit.