Posterior distribution of the GP parameters for α and P_rot for an RV-only run, including a QP-GP centered on the rotational period ~19 d and using anunconstrained prior on α. Samples are color-coded in accordance to their log-likelihood values, where those with a Δ ln L > 10 compared to the best solution are colored gray. The horizontal dashed line represents the maximum value at which we constrained the α parameter in order to exclude the plateau-like behavior. The plot is inspired by Stock et al. (2020b).