Three 2025 TESS transits reduce the fitted clock error for TOI-813 b under fixed transit and noise models

We measured 13 transit times of the known planet TOI-813 b from public TESS SPOC data. Ten times from 2018 to 2023 set an early clock. Three times from 2025 test that clock and extend the fit. The primary later-data test gives chi-square 7.082 for three measurements and p = 0.069. It includes the correlated prediction errors of the early clock. The full fit gives a period of 83.89604702 +/- 0.00013494 days. Its reference time at epoch 15 is BJD(TDB) 2459629.2128259. The reference-time error is 2.07 minutes. For a transit near 2030-11-11, the fitted clock error falls from 14.16 to 7.54 minutes. This comparison uses our fit through 2023 as the reference. All these errors assume a fixed symmetric transit shape and the stated residual-noise model. Corrected-flux stress tests shift that prediction by up to 26.19 minutes. Some tested shapes fit the earlier flux worse. These shifts are not a confidence interval. Some choices change the timing test outcome at the 5% level. Thus, the smaller fitted error is not a complete accuracy estimate. The data do not establish a stable timing signal. The package contains exact data windows, source hashes and headers, code, figures, timing tables, covariance matrices, and predictions through 2030.

TOI-813 b · TIC 55525572 · TESS · transit timing · ephemeris · public astronomical data · reproducible research