Left: lifetimes of ℓ = 0 (red), ℓ = 1 (blue), and ℓ = 2 (green) modes in Models A, B, C, and D (from top panel to bottom). The dashed line represents T_obs/ 2. Right: corresponding power spectra. The heights in power spectra are given in (m/s)²/μHz. For the sake of simplicity, all peaks are modelled by a Lorentzian, and we did not account for the different mode visibilities that depend on the angular degree. The resolution criteria (and so the time of observation) is taken into account for the height of the modes.