A fixed rotation model with flare removal gives bounds below 0.51% for repeating 1–3 h dips in six TESS sectors of TIC 234284556

TIC 234284556 had narrow flux dips in earlier observations. We test six later TESS sectors from July 2023 to July 2026. Dips must repeat at the published rotation period of 1.1066 d. We keep 84,141 two-minute samples in 110 rotation cycles. We remove large positive flare residuals. Each cycle has its own smooth stellar model. We fit symmetric triangular dips with full durations of 1, 2, and 3 h at 400 trial phases. At each phase, we calculate a nominal one-sided 99% upper bound. The largest bound across phase ranges from 0.278% to 0.502% of median flux. The two historical dip sectors give much larger fitted signals under the same model. Keeping the flares raises some bounds to 1.28%. Added-signal tests recover 79.1–100.2% of the added depth. The bounds are not a uniform detection threshold. These bounds require constant dip depth and phase within a sector. They also require an adequate smooth stellar model and independent errors between rotation cycles. They do not cover brief events, phase drift, or all possible dip shapes. We preserve the source data, exact hashes, code, numerical checks, signal injection tests, and figures. Instructions show how to repeat the analysis.

TIC 234284556 · TESS · stellar magnetospheres · transient dips · time series · reproducible research