Corrected TESS transit times are consistent with a constant period for K2-237 b from 2019 to 2025

We tested whether K2-237 b kept a steady period decrease of 0.36 seconds per year from 2019 to 2025. We fit 27 transits in three public 120-second TESS light curves. The main test uses corrected PDCSAP flux. The 2021 mean time is 26.7 seconds before the line through the 2019 and 2025 means, with a working standard error of 45.9 seconds. The central published rate predicts a time 234.7 seconds after that line. Both epoch and period are free. The fitted quadratic rate is +0.041 seconds per year. Its working 95% interval is [-0.119, +0.201] under independent visit errors and the stated noise model. A residual-block check widens this interval to [-0.134, +0.216]. Raw aperture flux gives [-0.595, +0.255] and permits both zero and the published rate. Thus, the result depends on flux correction and does not rule out common visit biases or smaller or variable period changes. The package contains seven accepted 2025 transit times, all 27 fitted events, exact source FITS files, provenance, figures, code, and reproduction steps.

K2-237 b · TESS · transit timing · orbital period change · public data · reproducible research