Same as Fig. 1 but for 15 yr [2003.01.24–2018.04.24] of TSI data from SORCE/TIM. In total, 5508 days are considered. This corresponds to about 82 632 data points at a cadence of 1.6 hours. Orange lines represent the same Kepler-like timespan K_n as is shown in Fig. 3. The GLS, ACF, and PS methods do not show a definitive detection signal of the rotation period. GPS method shows a prominent peak at 4.12 days corresponding to the solar rotation period value of 26.1 days.