Posterior distributions of the model parameters of equation 4 for Ca I. The top-right panels show the CCF of all eight epochs combined, binned to a common phase grid (top), and the model with parameters equal to the median of their posterior (bottom panel). For Ca I the signal is poorly visible by eye in the CCF, but for Cr I and Fe I it can be discerned (see below). The fit of Na I is poorly converged and consequently we classify the Na I signal as tentative.