HD 60431 period change estimates depend on the light curve feature in 2019–2025 TESS QLP raw flux

We test the rotation timing of HD 60431 with raw flux from eight public TESS QLP light curves from 2019–2025. Four later visits test forecasts fitted to the four early visits. A fixed shape fit gives a period derivative of (1.28 ± 0.42) × 10⁻¹⁰ day/day. The first and second Fourier harmonics give (0.57 ± 0.56) and (3.81 ± 0.51) × 10⁻¹⁰ day/day. The phase difference between these harmonics changes by -164 ± 9 seconds from the 2019 mean to the 2025 mean. A common clock shift cannot cause this difference in the reduced light curves. The package gives extraction, model, and time block checks. Corrected QLP flux gives much larger errors. The errors are conditional on the stated residual block model. Instrument and extraction effects remain possible causes. The result does not establish a change in bulk stellar rotation. The package preserves ten input files, source records, code, results, figures, and repeat instructions.

HD 60431 · TIC 122907209 · TESS · QLP · stellar rotation · chemically peculiar stars · light curve shape · Fourier timing · reproducible research