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astro-ph.EP · Earth and Planetary Astrophysicsastro-ph.IM · Instrumentation and Methods for Astrophysics

TESS transit times from 2018 to 2026 agree with reported period changes of WASP-12 b and HAT-P-7 b, do not agree with 9 of 23 other reported changes, and show a curved KELT-20 b ephemeris

Question: Do TESS observations from 2018 to 2026, analyzed alone with one method, agree with the 26 hot-Jupiter orbital period changes (dP/dt) that Wang et al. (2024) reported from data up to January 2023? Method: We measured 3,620 transit mid-times from TESS 2-minute light curves (sectors 1 to 107) for 25 of the candidates and for 59 random control hot Jupiters. The controls show that the timing errors are calibrated (standard deviation of dP/dt divided by its error = 0.96). We compared a constant period with the reported dP/dt in three tests: a TESS-only fit, a forecast of the 2023 to 2026 TESS times from earlier data, and a fit with one pre-TESS archive epoch. Results: The reported dP/dt predicts the 2023 to 2026 times better than a constant period for WASP-12 b and HAT-P-7 b. The TESS times alone prefer a constant period for WASP-45 b, WASP-46 b and WASP-17 b. The forecast test with a pre-TESS epoch prefers a constant period for TrES-3 b, WASP-10 b, WASP-11 b, WASP-16 b, WASP-22 b and XO-4 b. For 14 candidates, the result is inconclusive. In the control sample, KELT-20 b has a TESS-only period increase of +57 +/- 12 ms/yr (4.7 sigma). Sector 14 gives most of this signal. Independent pre-TESS times from the literature agree better with this curved ephemeris than with a constant period (chi2 25.6 against 57.4 for 9 times). Another planet in sector 14 shows no offset. Thus a sector-wide clock error does not explain the signal. The increase agrees in direction with the light-travel-time effect of the brown-dwarf companion that Yang et al. (2026) reported. Limitations: Six disfavoured results depend on one archive epoch. A constant dP/dt cannot model companion orbits. The KELT-20 b result depends mostly on one sector and needs independent 2019 to 2020 times for confirmation.

hot Jupiters · orbital decay · transit timing · TESS · period derivative · KELT-20 b · WASP-12 b · WASP-45 b · WASP-46 b · light-travel-time effect · reproducibility test

Admitted 2 citing publications

References

6
  1. reviewshttps://arxiv.org/abs/2310.17225

    Source of the 26 reported period-change candidates and their dP/dt values that we test.

  2. supports, useshttps://arxiv.org/abs/2606.02705

    Reports a brown-dwarf companion of KELT-20 from astrometry and transit timing; we use its table of literature mid-times and our TESS-only curvature agrees in direction.

  3. https://ui.adsabs.harvard.edu/abs/2022ApJS..259...62I/abstract

    Earlier homogeneous TESS transit-timing study of hot Jupiters (Ivshina and Winn 2022).

  4. usesdoi:10.1086/683602

    batman transit model used for all fits.

  5. useshttps://exoplanetarchive.ipac.caltech.edu

    Planet parameters and archive mid-times (pscomppars and ps tables, queried 2026-11-08).

  6. useshttps://archive.stsci.edu/missions-and-data/tess

    TESS SPOC and TESS-SPOC light curves (415 files, MAST URIs and SHA-256 in files/data).

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