Later TESS sectors (2022-2026) do not repeat the planet-phase flare clustering of AU Mic, K2-25 and TOI-540; published Anderson-Darling p-values change with the phase origin

Question: Ilin et al. (2024) reported tentative clustering of flares at the orbital phase of the innermost planet for AU Mic, K2-25 and TOI-540 (Anderson-Darling p = 0.12, 0.18, 0.084), and their best candidate was HIP 67522. Their TESS data stopped in July 2022. Method: We used TESS SPOC 2-min light curves from later sectors (2022-2026) as an out-of-sample test of the 13 TESS systems in their final table. We used their de-trending code, the AltaiPony flare finder, their ephemerides and their coverage-weighted expected phase distribution. We vetted the new candidates by eye. Results: With their flare table we reproduce all 13 published p-values. The Anderson-Darling statistic depends on the arbitrary phase origin, and for transiting systems the published values use origin 0 only. Over 40 origins the p-value for the old AU Mic flares goes from 0.003 to 0.32, and for HIP 67522 from 0.0013 to 0.47. An origin-free Kuiper test gives 0.026 (AU Mic), 0.026 (K2-25, 3 flares), 0.22 (TOI-540) and 0.010 (HIP 67522) for the old flares. In the new sectors, no system has a Kuiper p below 0.05 (AU Mic 0.41 with 29 flares, K2-25 0.53, TOI-540 0.66). For the phase arcs with the largest excess in the old flares, the new data put 9 of 40 flares of the three systems in the arcs. The null expectation is 7.8 (p = 0.37), and the full old effect predicts 17.8 (power 0.96). Automated-only vetting and an ED > 3 s cut give the same result. Limitations: The new data exclude the old effect size but not an effect of half that size (power 0.47) or intermittent interaction. K2-25 and TOI-540 have only 3 and 8 new flares. Our flare detection recovers 84% of the published flares in the same sectors.

stellar flares · star-planet interaction · TESS · AU Mic · K2-25 · TOI-540 · HIP 67522 · Anderson-Darling test · Kuiper test · out-of-sample test · replication · M dwarfs