Free source timing offsets remove more than 90% of period change information in 43 of 115 systems in a 2022 transit catalog
We measured how much information about a constant orbital period change remains when each timing source has a free constant offset. We used the 2022 transit time catalog of Ivshina and Winn. We kept individual transit times, kept one row per orbit number, and used a minimum timing error of 25.92 seconds. The main test has 4,378 distinct epochs in 115 systems with at least three years of data and two sources. We compared weighted quadratic fits with a common intercept and with one intercept per source. At fixed errors, 43 systems retain less than 10% of the information about period change; 13 retain less than 1%. The median retained fraction is 0.226, and the median formal error increases by a factor of 2.10. In 108 systems present in all seven analysis choices, 39 to 47 systems retain less than 10%. WASP-12 keeps a clear negative quadratic signal with free source offsets. The old XO-3 data have a factor of 8.35 increase in formal error. These results measure a limit set by the sampling, source labels, and error model. They do not show that source errors exist or establish a new case of orbital decay. We provide the input tables, source history, code, selection audits, figures, and numerical and simulation checks.
transit timing · orbital period change · source offsets · information loss · exoplanets · TESS · reproducible data analysis
References
4- usesdoi:10.3847/1538-4365/ac545b
Tables 3 and 4 supply the linear ephemerides, transit times, errors, orbit numbers, and source labels. We use the authors' fixed GitHub release and preserve source credit.
- doi:10.1093/mnras/stz2620
Prior work used a common analysis of transit light curves and examined how noise models affect timing trends.
- doi:10.48550/arXiv.2310.17225
Prior work tested period change candidates by removing one transit at a time. Our test allows a constant offset for a whole source.
- TESS 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
Related SCI work compared recent TESS times with archive ephemerides. We test a different question in a fixed 2022 timing catalog and do not reuse that study's data or code.
Cited by
12 publicationsPublic catalog entries on Sciscape.
- Eight of ten quadratic transit timing trends that pass single-transit removal fail a time group test under fixed errors in a 2022 catalog
This related study tests source offsets in the same catalog. We compare a different source of model dependence.
- usesFree linear drift in a new source removes over 99% of added period change information in 88 of 115 four-year quadratic transit designs with three times and 30-second errors
We use its source offset model and sample rules through the later SCI design study.
- usesTwenty-six TESS transit times in 2018 to 2026 do not require period change for WASP-99 b with extra Gaussian scatter
Its verified archive supplies our unchanged copy of the fixed Ivshina and Winn Table 4. We use no code from it.
- usesFour-year endpoint pairs minimize formal period change errors in 94 of 115 quadratic transit timing designs with 30-second times and free constant source offsets
We use its sample rules and reduced check data. Independent code reproduces its 4,378 selected row IDs and 115 old formal errors. We add an exact two-visit scheduling rule and a catalog design benchmark.
- usesOptimized period change intervals are at least 10 percent shorter in 11 of 115 transit systems with 60-second source bounds and fixed Gaussian errors
We use its fixed 115-system primary sample and its unchanged MIT selection code. We extend the free-source limit with finite source bounds and new optimized linear estimates.
- usesSix TESS sectors from 2018 to 2026 leave constant period change in WASP-99 b unresolved with scaled errors
Its study of free source time origins motivates our sector-offset stress test. We reuse neither its data nor its source code.
- A constant period fits 103 WASP-121 b TESS transit times with a shared transit shape and independent errors
This related study measures the loss of period-change information after free source offsets. We read it before fitting. No code or data are reused.
- supportsShared training uncertainty limits the constant-period mean offset to 1.8 standard errors for 35 WASP-12 b TESS transits assuming fixed shapes and independent timing errors
The timing-source offset study motivated our shared sector-offset sensitivity test. We reuse no measurements or code.
- Evidence for period growth in WASP-46 b depends on the error scale in nine TESS sectors
Related work shows the loss of period-change information when timing sources have free offsets. We reuse no code or measurements.
- Separate sector clocks improve the KELT-24 fit in a test of 67 TESS systems under independent Gaussian errors with fixed catalog variance ratios
This source offset study motivates a test of groups within the TESS source. We reuse no code or derived data.
- usesFree linear drift in a new source removes over 99% of added period change information in 88 of 115 four-year quadratic transit designs with three times and 30-second errors
We use its source offset model and sample rules through the later SCI design study.
- Two released WASP-43 b transit rows fail a 1000 s check; screened times permit a constant period with a free epoch and fitted Gaussian noise
This related work tests information loss from free source timing offsets in a different catalog. We test a global reference time and do not reuse its data or code.