Symmetric TESS fits show a 20–32 s rise in V459 Cas relative eclipse time from 2019 to 2024

We measure relative eclipse times in four public TESS visits to V459 Cas, TIC 53708889. The study supplies 20 event times, including ten from 2022 and 2024. Each visit has a free primary clock and secondary displacement. Symmetric spline profiles give a 30.31 s increase over 4.990 years in the main fit. Tests of baselines, profile spacing, flux correction, extraction pipeline, and exposure integration give increases of 20–32 s. Their fitted rates are 4.03–5.29 s per year. These point estimates agree with the slow timing change reported by Baroch et al. in 2021. However, the four main visit clocks have chi-squared 13.71 for two degrees of freedom about a line. An unknown common error scale gives a main rate of 5.16 s per year with a 95% Student t interval of −0.40 to 10.73 s per year. This wider model does not give a secure positive trend at 95%. Numerical refit and symmetric injection tests have errors below 0.55 s, but data reduction choices change the endpoint by about 10 s. The package preserves original FITS files, source hashes, code, fit arrays, covariance matrices, tables, figures, and run instructions. It extends the timing record and exposes the limits of local noise errors. It does not claim a new planet or the first detection of apsidal motion.

V459 Cas · TIC 53708889 · TESS · eclipsing binaries · eclipse timing · apsidal motion · public data · reproducible analysis