Two fixed catalogs give different timing flags for six of 86 hot Jupiters in one TESS transit model
We tested whether timing flags agree between two fixed joint-fit catalogs when the same TESS observations have new, uniform transit fits. We selected 109 known hot Jupiters from an earlier 153-planet SCI sample by a unique complete ExoClock III source match. All selected periods, reference times, and errors agree exactly with the original CDS table. We measured 823 individual transit times from public two-minute SPOC light curves. For 86 planets, 637 transits occur after 2021 and more than 30 days after the last listed input of Ivshina and Winn (2022). The actual minimum gap is 713.7 days. For the same measured times, six offsets exceed three combined error scales against ExoClock III and none do against the 2022 catalog. The forecast error is the largest allowed by the quoted period and reference time errors over every allowed covariance. These are conditional flags, not detection probabilities. Four of the six flags persist in all five tested transit models. KELT-20 b and WASP-2 b cross the threshold when the model changes. Median absolute offsets are 0.541 and 0.650 minutes; the flag counts do not establish an overall accuracy ranking. KELT-20 b has nearly the same central forecast in both catalogs, but different stated errors. We preserve the source snapshots, retained light curve columns, 823 measurements, 159 fits, figures, independent arithmetic checks, and repeat instructions. This retrospective one-sector test establishes a catalog-dependent result. It does not establish a new planet or a physical cause for any offset, and it does not test the newer ExoClock IV release.
TESS · transit timing · ephemeris · catalog comparison · hot Jupiters · reproducible astronomy
References
11- usesTESS 2-minute transit times of 153 bright hot Jupiters missed the NASA Exoplanet Archive default ephemeris predictions by more than 3 sigma for 33 planets (sectors 21-107) sci:sha256:1895bf428f65ddb5d621f1e1b67e6fe70b4074599f4ced66ffdc1cf0a99b69fe
We reuse the selected planet names, one-sector choices, composite archive snapshot, and original timing outputs. We preserve its signed package and unchanged code. We independently fit all 109 ExoClock III matched light curves.
- supportsPublished period and epoch pairs reduce the median absolute TESS timing offset from 6.24 to 0.66 minutes in a 136-planet archive test sci:sha256:b58d1b0c474456bc46005d826d14c6f118754fa4209814de10bc353bfa85f62c
It showed that complete published period and time pairs remove many inherited offsets and independently fitted selected systems. We extend the measurement check uniformly to all 109 matched targets.
- supportsDated fits reduce median TESS transit-time offsets from 6.63 to 0.74 minutes for 129 hot Jupiters sci:sha256:f4852f4f6a0d8b63ff28d3739921249429bd47477dcf329a7f040ba7ed98c406
It tested dated ephemerides with a maximum prediction error bound and noted the known HAT-P-7 timing trend. This is prior context for our uniform two-catalog test.
- usesJoint 2022 ephemerides predict later TESS times more accurately than the 2026 archive composite values for 83 of 92 hot Jupiters sci:sha256:bdb906c50c677c7cf55e60c7368b884b6dc21fa1e8b7e9576e90a706b25e4899
Its fixed IW22 comparison motivated our second catalog and later-data rule. We independently fetched the same pinned primary tables and made new measurements for all 109 matched systems. We compare ExoClock III directly with IW22.
- usesdoi:10.3847/1538-4365/ac9da4
ExoClock III table 7 provides the fixed 2023 catalog. All 109 selected archive pairs and marginal errors exactly match the original CDS table.
- usesdoi:10.3847/1538-4365/ac545b
IW22 tables 1, 3, and 4 provide TIC matches, joint ephemerides, and the last input dates. We preserve the repository commit and tables.
- doi:10.48550/arXiv.2511.14407
ExoClock IV is a newer release. Our comparison tests the fixed III release and makes no claim about the current service.
- usesdoi:10.26133/NEA12
The saved Planetary Systems response supplies source rows for all seed names. We check the selected rows against CDS.
- usesdoi:10.26133/NEA13
The seed Planetary Systems Composite Parameters snapshot defines target cuts and initial durations and depths.
- usesdoi:10.17909/t9-nmc8-f686
Public mission SPOC two-minute light curves provide the new timing measurements. Source product URLs, FITS hashes, time headers, and exact retained columns are preserved.
- usesdoi:10.1086/683602
The independently installed batman package supplies the exposure-integrated symmetric transit template.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- usesExoClock IV linear forecasts reduce median timing error for 93 selected systems after 2023 under one transit model
We reuse the signed light curve arrays, 109 default transit fits, 11 model checks, source records, and fitting code.
- Nine of twelve quadratic clocks selected from a 2022 catalog have larger later TESS errors than linear clocks under fixed timing errors
Prior work compares two fixed linear catalogs with later TESS observations. This study compares polynomial orders fitted to identical early timing rows and uses Release D times.
- Local fits to TESS sector 104 place one TOI-1130 c transit 2.2 to 2.7 minutes after the 2024 forecast
This fixed-catalog comparison shows that timing flags depend on the forecast and its stated error. Our result is limited to the specified 2024 forecast.