Cubic baseline fits shift a 2024 TESS primary eclipse arrival time of DI Herculis by 84 seconds
We test the effect of local flux models on eclipse times of DI Herculis. We use public two-minute SPOC data in TESS Sectors 26, 80, and 81. Coverage cuts retain four primary and four secondary eclipses in 2020 and 2024. We align the profiles with empirical 2020 templates. For the Sector 81 primary eclipse, we change only the cubic baseline window. Half-widths from 0.36 to 0.52 days give an 84.0-second range in arrival time. Its formal reference error is 10.6 seconds. A 48-configuration matrix tests flux column, polynomial degree, window width, and profile width. It gives a 227.4-second range for that event. Conditional residual block estimates give standard deviations of 28.8 to 67.2 seconds as block length changes from 10 to 60 minutes. The reference secondary eclipse clock is 10.55017876 days. Its period spans 10.55017761 to 10.55018382 days across the tested matrix. Model ranges are sensitivity measures, not confidence intervals. The measurements are template arrival times; a physical eclipse model is needed for conjunction times and apsidal motion. The package preserves the three input FITS files, source URLs and hashes, code, all timing fits, controls, figures, and offline reproduction steps. This study adds measurements and model tests for the 2024 data. It makes no new planet or revised precession claim.
DI Herculis · TIC 358517121 · TESS · eclipsing binaries · eclipse timing · apsidal motion · stellar variability · baseline sensitivity · public data
References
2- usesdoi:10.3847/1538-4357/ac4f65
This Sector 26 study motivates the profile tests. It reports primary eclipse anomalies, secondary asymmetry, and extra timing errors. We analyze the later Sector 80 and 81 data and use its printed secondary epoch as a template coordinate.
- usesdoi:10.17909/T9-NMC8-F686
Public TESS two-minute light curves. We use only TIC 358517121 in Sectors 26, 80, and 81. Exact product names and SHA-256 digests are in the supporting files.
Cited by
4 publicationsPublic catalog entries on Sciscape.
- Quadratic background fits give false asymmetry changes in symmetric eclipse tests at DI Herculis sample times
This study reports background dependence in a primary eclipse timing measurement. Our test concerns a fixed odd flux component in secondary eclipses.
- Local fits with a cubic baseline give times 11.8 hours apart for one V380 Cyg eclipse in corrected TESS sector 82 flux
We read this independent example of local-baseline effects on DI Herculis eclipse times. We use separate data and code.
- Linear baseline fits give a four-minute decrease in V453 Cyg eclipse spacing from 2019 to 2024
Related DI Her work shows sensitivity to a local brightness baseline and motivates reporting adverse timing controls.
- usesSymmetric simulated eclipses give an apparent loss of asymmetry in a DI Herculis template test
We adapt MIT extraction and spline code and reuse the three public FITS files and download record. We check their digests and the public archive again.