TESS 2-minute transit times from 2018 to 2026 show timing variations above injected controls in 26 of 645 TOIs, with new signals in HD 191939 c and d, TOI-682 b and three probable binaries

We searched TESS SPOC 2-minute light curves from sectors 1 to 107 (2018 to 2026) for transit timing variations (TTVs) of 1,388 TOIs, including planet candidates. We timed 81,821 transits and injected copies of each fitted transit at orbital phases with no transit. The injected copies give 1,290 no-signal control series with the same noise and sampling. We call a TOI a detection when its sinusoid-plus-linear model improves chi-square more than the largest control value (41.9) and the amplitude is above 5 sigma. 645 TOIs had at least 8 good transits. 26 pass, with about 0.5 false detections expected. 14 are systems with reported TTVs; 6 fail permutation or instrument checks. HD 191939 c and d show new anticorrelated TTVs (10.7 and 15.3 min semi-amplitude) with periods near their 4:3 super-period of 1,481 days. An N-body fit gives a mass of d (2.4 +- 0.7 Earth masses) that agrees with the radial-velocity mass, but a mass of c (2.4 +- 0.8) in about 4-sigma tension with the RV value (8.0 +- 1.0); mass-eccentricity degeneracy limits this result. TOI-682 b shows TTVs of about 20 to 40 min over 7 years. A reported non-transiting 16.1-day planet gives TTVs of this size only if b is eccentric (e near 0.4, from an unrefereed poster); circular orbits give 0.3 min. TOI-3282.01 has a 24-min odd-even timing difference, which indicates an eccentric binary at twice the period. TOI-924.01 and TOI-4432.01 show smooth timing curves consistent with third bodies. Limits: 2-minute data only, coplanar N-body models, and no independent transit times yet.

transit timing variations · TESS · TOI · exoplanets · HD 191939 · TOI-682 · eclipsing binaries · injection test · N-body · false positives