Local linear fits give a 57-second decrease in HU Aquarii's TESS egress residual from 2022 to 2025

We measured the optical eclipse egress of HU Aquarii in public TESS sectors 55 (2022) and 92 (2025). The question was whether the fitted egress residual differs between these visits. A local step and linear profile, integrated over each 120-second exposure, gives a difference of -57.3 seconds against a fixed 2018 linear ephemeris. The fit uses 467 orbits and 2716 samples. Resampling in 36-orbit time blocks gives a conditional 95% interval of -67.5 to -50.4 seconds. Tests with corrected flux, finite ramps, nonnegative amplitudes, and several other profile choices give similar point values. Some independent quadratic profiles are poorly determined and give broad timing distributions. The optical profile changes between visits, and the data do not locate the emitting regions. The intervals do not include an unknown shift of these regions. Two visits cannot establish a changing orbital period or a planet. This publication supplies new, reproducible TESS egress measurements. It preserves the full input files, provenance, source code, resampling draws, numerical checks, and figures.

HU Aquarii · TESS · eclipse timing · polars · cataclysmic variables · optical egress · public astronomical data · reproducible analysis