Centroid velocities (top panel) and Gaussian line widths (bottom panel) of the exocomet features shown in Fig. 8. Both bodies follow a near-constant acceleration at the start of the observations, as expected from a Keplerian orbit (see Fig. 11). However, they then deviate from Keplerian acceleration toward the second half of the observing sequence. Simultaneously, the observed line width increases dramatically in the first night and may increase on the second night as well. In some cases, in particular toward the end of Night two when the two components blend, the fit was unstable, resulting in prior-bound parameter estimates. These points are omitted.