Symmetric fits to two-minute TESS data show wider TOI-1518 b transits in late 2024 than in 2022

Does the transit of TOI-1518 b continue to widen after the change reported for 2019 to 2022? We analyze five public TESS sectors at the same 120-second exposure time. Fixed coverage rules accept 58 complete transits. The primary comparison uses 27 events in 2022 and 22 in late 2024. Nine events give an intermediate check. The intrinsic full width at half depth of a stretched reference profile increases by 7.256 minutes. Event resampling gives an error of 0.231 minutes and a 95% interval from 6.800 to 7.710 minutes. This error excludes model dependence and common calibration errors. Aperture flux, baseline, window, and reference-shape checks give increases from 7.066 to 7.343 minutes. A separate spherical fit with free common geometry gives an increase of 8.206 minutes. Synthetic tests explain why these width measures can differ. A changing spherical path with a true width increase of 8.055 minutes gives only 6.728 minutes through the reference-profile estimator. Tests with no true change and observed residuals give apparent changes near 0.5 minutes. Both real-data shape models support continued widening through late 2024. The direction and scale agree with the earlier transit-path trend under the tested assumptions. Only two sectors per primary year group limit control of shared errors. We supply all original FITS inputs, source hashes, selection records, code, event measurements, control results, and figures.

TOI-1518 b · TESS · transit width · nodal precession · signal recovery · public astronomical data