PSD of KIC 9139163 (gray) with overall background from Eq. (25) and median values reported in Table 1 (thick green line) with the additional Gaussian envelope included (dotted green line). The solid black line represents the smoothed PSD by 81.4 μHz. The single background components of constant photon noise (dotted), power law (dashed), granulation and faculae (dot-dashed), and Gaussian envelope (double-dot-dashed) are shown in blue. Upper panel: model ℳ₁ accounting for one Harvey-like profile. The arrow indicates the presence of a kink that is not reproduced by the model. Lower panel: model ℳ₂ accounting for two Harvey-like profiles. The winning model ℳ₂ is strongly favored as it yields a Bayes’ factor lnℬ₂₁ = 58.2 ± 0.2 over its competitor.