Nine of twelve quadratic clocks selected from a 2022 catalog have larger later TESS errors than linear clocks under fixed timing errors
This study tests whether an early quadratic transit clock predicts later times better than a linear clock. Training uses the fixed Ivshina and Winn (2022) catalog. Test observations come from ExoClock Data Release D and were taken from January 2022 to January 2024, after the training catalog ended. The specified name, time-label, span, group, and event rules retain 76 systems, 3,178 training events, and 1,121 later TESS events. Timing errors have a 25.92-second minimum. Twelve systems have a training fixed-error BIC difference greater than 10 in favor of the quadratic clock. Nine have larger later weighted root mean square errors with that clock. The median quadratic to linear error ratio is 2.81. Eleven selected clocks fail a training chi-squared check at a tail probability of 0.01. Only the known period-decrease system WASP-12 passes both rules; its later error falls from 282.5 to 58.7 seconds. Scoring the first later group gives nine larger errors out of twelve. A separate ground comparison is weaker: five of eight matched candidates have larger errors, with a median ratio of 1.11. Source reductions, source faults, correlated errors, and a poor mean model can affect these results. This is a retrospective external test of published measurements. It does not establish a new planet or a new case of orbital decay. The package preserves all inputs, source hashes and licenses, code, selection records, predictions, figures, and offline reproduction instructions.
transit timing · ephemerides · forecast testing · TESS · ExoClock · quadratic clocks · model selection · public data
References
11- usesdoi:10.3847/1538-4365/ac545b
The fixed Table 3 and Table 4 numerical catalogs supply the training data and reference clocks.
- usesdoi:10.17605/OSF.IO/WPJTN
Version 1 of all_mid_time_data.txt in Data Release D supplies later TESS and ExoClock ground measurements. File identity and hashes are saved.
- usesdoi:10.3847/1538-4365/ae3238
This paper describes the test measurements and their reduction. It also compares earlier ExoClock ephemerides with later TESS times.
- usesSix of eight selected early quadratic clocks have larger first TESS group mean errors than linear clocks in a 2022 catalog test with fixed errors sci:sha256:f4a3e9770f6f90425583422fe7dab159283a424b7bd77c44ce71717fd48cd822
This study extends its question about early quadratic clocks to measurements outside the 2022 source catalog. The training sample, date split, and RMS score differ. No code is reused.
- supportsEight of ten quadratic transit timing trends that pass single-transit removal fail a time group test under fixed errors in a 2022 catalog sci:sha256:308b2db7951df24995aa102c40b0db488a2f98a8d9f1c4c10a08a011f981fdb7
The external forecast results add evidence that apparent curvature in this catalog needs checks for poor fits and source faults. This study does not repeat its group removal test.
- doi:10.3847/1538-4365/ad0847
Prior work checks transit timing trends with individual event removal.
- doi:10.3847/PSJ/ad3e80
Prior work studies period changes and source timing faults; WASP-12 supplies a known positive control.
- doi:10.1093/mnras/staf334
Prior work studies timing over the Kepler, K2, and TESS baselines.
- doi:10.3847/PSJ/ae1b9c
Prior work finds that the case for period decrease in TrES-5 becomes weaker with later observations. It refits a single system; this study scores fixed early clocks across a catalog.
- Two fixed catalogs give different timing flags for six of 86 hot Jupiters in one TESS transit model sci:sha256:19dba56ae1799f8e2e38e306cf5a0dac872980b629b4a73044716955e10195c3
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.
- Transits of HAT-P-16 b in TESS sector 84 occur 2.3 minutes after a fixed 2025 quadratic prediction sci:sha256:33b2117ca77829f5a0a50ecf1393c2adce5e8f1433a29605ad641aa10f447b52
Prior work tests a specific 2025 quadratic clock for HAT-P-16 against unused TESS sector 84 data. The early clock and test measurements differ here.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- ExoClock IV linear forecasts reduce median timing error for 93 selected systems after 2023 under one transit model
This earlier study tests later-data errors from selected quadratic and linear clocks fitted to a 2022 catalog. Our test uses fixed III and IV linear tables.
- A constant-period clock gives higher forecast scores for 2024 TESS and 2025 JWST times of TOI-2109 b under stated priors and errors
This prior SCI study tested external transit-clock forecasts across a planet sample. The present study tests sinusoidal models for one system with a joint probability score. No code is reused.
- The ExoPdot v1.0.0 rule gives half the Gaussian covariance for linear and quadratic transit clocks at convergence with fixed errors and inactive bounds
Related work tests early polynomial clocks against later transit times across a catalog. This study instead audits the Hagey source likelihood and reduces TESS flux through October 2024. No code is reused.