Local circular fits to 40 TESS eclipses do not resolve a mean depth change for KELT-20 b from 2019-2022 to 2024

We tested whether the mean TESS eclipse depth of KELT-20 b changed between 2019-2022 and 2024. We used seven public 120 s SPOC light curves and kept 40 eclipses with adequate coverage. We fixed a circular orbit and spherical geometry from prior work. Each event had a separate local quadratic baseline. We fitted sector time corrections to primary transits before fitting eclipses. The information-weighted depths were 141.3 ppm in 2019-2022 and 132.3 ppm in 2024. The 2024 minus 2019-2022 difference was -9.0 ppm. Its conditional 95% interval from whole-event resampling was [-56.2, +36.5] ppm. A check that grouped residuals by sector gave [-76.1, +58.1] ppm. All planned changes in baseline, window, flux product, timing, geometry, and event blocks gave intervals that included zero. One of six dependent off-eclipse controls gave +39.6 ppm with an interval of [+3.6, +74.9] ppm. This control shows that local structure can give apparent epoch differences. The data do not resolve the tested mean change. The result does not establish constant planet brightness or reject short changes seen with another instrument. We preserve the original data, provenance, event results, figures, code, local plan, and reproduction instructions. This study adds a defined epoch contrast and sector 81 to prior TESS eclipse work.

KELT-20 b · MASCARA-2 b · TESS · secondary eclipse · optical variability · null result · public data · reproducible analysis