Symmetric fits to EK Cep SAP data show a decreasing eclipse phase in 2019–2024

We tested the secondary eclipse phase of EK Cep in 12 public 120-second TESS SPOC light curves. Symmetric profile fits to SAP flux give 107 accepted eclipse centers. Twenty-seven secondary events have accepted primary events on both sides. We multiply their local phase by a fixed 4.427794-day period. Equal weights for nine sector means give a slope of -28.53 seconds per year. The approximate HC3 and Student t 95% interval is -31.88 to -25.18 seconds per year. The fitted decrease between endpoint sector means is 146.46 seconds. SAP baseline, window, profile, edge midpoint, and deletion controls retain the decrease. Four annual means also retain it. This result has the direction and scale of known apsidal motion. A PDCSAP fit gives much larger scatter and an interval that includes zero. In sector 78, secondary cycle 613, its fitted center is 490.53 seconds earlier than the SAP center. A flux shape difference is visible in that event. We do not establish a precise slope change between products or a unique physical cause. Independent synthetic shapes recover fixed and imposed phase slopes within 0.05 seconds per year at the accepted timestamps. These tests do not calibrate total uncertainty. The release adds event times through 2024 and flags a specific product difference. It preserves source FITS files, hashes, code, selection records, results, figures, and repeat instructions.

EK Cep · TIC 322262620 · HD 206821 · TESS · eclipse timing · apsidal motion · SAP · PDCSAP · flux processing · reproducible data