Process of creating the light curve of an AAB star and its PDSs. Panels a and b: Individual light curves of two red-giant stars (KIC 1871314 and KIC 2140446). Panel c: Combined artificial light curve. The shaded light gray regions indicate areas where data points are not available. Panel d: PDS of the light curve from panel c. In this panel, the dashed blue lines represent granulation background components, the dotted gray line indicates the white noise component, and the green line shows the total background fit. Panel e: Background-corrected PDS in the frequency range of ν_max±3σ_env. The vertical dashed red line in panels d and e indicates the location of ν_max estimated as explained in Sect. 3.1.2.