Transits of HAT-P-16 b in TESS sector 84 occur 2.3 minutes after a fixed 2025 quadratic prediction
We test the published quadratic timing model for HAT-P-16 b with nine complete transits from TESS sector 84. That sector is absent from the listed TESS sample in Sonbas et al. (2025). We fit the transit shape, local brightness baseline, and transit times from public 120-second SPOC data. The mean measured time is 2.27 ± 0.20 minutes later than the fixed quadratic prediction. Changes to the baseline, limb darkening, time window, and flux product give offsets from 2.18 to 2.32 minutes. The quoted marginal parameter errors permit a model error of at most 0.54 minutes for any parameter covariance. Under those errors and independent measurement noise, the offset is at least 3.9 combined standard errors. Extra model or historical timing error can reduce this diagnostic. The result does not rule out orbital decay. A separate audit of an earlier SCI survey finds six mixed-source period and reference-time pairs with a unique complete source row. Three offsets above five reported errors fall below 1.5 errors when each period is paired with the reference time in that row. The other 53 cases without a matched row remain untested. We preserve all 12 light curves for three planets, 70 measured transit times, the archive responses, source hashes, code, figures, and instructions.
HAT-P-16 b · TESS · transit timing · orbital decay · ephemerides · data provenance · WASP-20 b · KELT-18 b
References
10- 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 frozen default archive rows, transit measurements, and target list to audit source pairing, select three planets, and compare independent light curve fits.
- challengesdoi:10.3847/1538-3881/ae0f19
Nine sector 84 transit times occur 2.27 minutes after the fixed HAT-P-16 b quadratic prediction in Table 7. The test is conditional on quoted parameter errors and does not exclude orbital decay with revised data or errors.
- usesdoi:10.1093/mnras/stae854
Provides the HAT-P-16 b period-source row used for the reference audit and a prior timing study of this system.
- doi:10.1093/mnras/stad204
Prior comparison of physical timing models for HAT-P-16 b.
- usesdoi:10.1002/asna.20224012
Provides the separately fitted reference times in the six mixed-source composite cases. The paper fixed periods when it fitted transit centers.
- usesdoi:10.3847/1538-4365/ac9da4
Provides period-source rows used in the reference audit, including WASP-20 b.
- supportsdoi:10.3847/1538-4365/ac545b
The shorter KELT-18 b period is already known. We use its ephemeris only to locate transit windows and count cycles.
- supportsdoi:10.32023/0001-5237/70.3.2
The shorter KELT-18 b period was already reported in 2020; our comparison is not a new period-change claim.
- usesdoi:10.1086/683602
We use batman-package 2.5.2 for transit light curves with finite exposure integration.
- usesdoi:10.1117/12.2233418
Describes the SPOC pipeline that made the public TESS light curves used in this analysis.
Cited by
2 publicationsPublic catalog entries on Sciscape.
- Nine of twelve quadratic clocks selected from a 2022 catalog have larger later TESS errors than linear clocks under fixed timing errors
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.
- The TOI-1516 b table in Sonbas et al. (2025) has inconsistent timing residuals