Example of a fit to the Ca II doublet (K-line in the top panel and H-line in the bottom panel) of a blueshifted exocomet observed on December 10, 2019. The exocomet is modeled as a single component, and the disk line as a blend of two. The narrow fitting region is restricted to the blue side of the disk line to avoid additional unrelated exocomet components. Because the CaII lines are covered by three spectral orders of HARPS, the fit is carried out over four wavelength regions simultaneously. The posterior distribution of models is shown by the orange lines. Posterior distributions for model parameters are shown in Fig. 4.