A local period scale reduces the effect of time coordinates below 0.1 s in 12 GG Orionis eclipses from TESS Sector 98
We test three time coordinates for 12 complete eclipses of GG Orionis in TESS Sector 98. We hold the exposures, flux samples and clock weights fixed. A change from TESSCut times to QLP times or geometric target times changes the unscaled primary-to-secondary spacing by 1.168 to 1.182 seconds. Scaling that spacing by the fitted local period reduces the change to 0.049 to 0.067 seconds in three flux extractions. A fixed linear change of measured times leaves this ratio unchanged. The small curvature of the observed time map explains the remaining effect. For all 24,162 Sector 98 rows, QLP minus geometric target time agrees within 0.003330 seconds with the prior CCD 2 prediction of 1.96 seconds. This extends that reference check to one target in Sector 98. An independent spline analysis also reproduces the known decrease in eclipse spacing from Sector 6. It gives 271.6 seconds, with a 3.7-second conditional error after scatter inflation. Tested spline methods give decreases of 267.6 to 274.1 seconds; a coarse bracketing method gives 260.9 seconds. The small coordinate effect does not imply absolute clock accuracy or remove flux and profile errors. We preserve the raw data, source hashes, prior-work record, code, figures, controls and instructions for an offline repeat.
GG Orionis · TESS · eclipse timing · time coordinates · barycentric correction · QLP · reproducible astronomy
References
10- TESS data show a 275 s decrease in the interval from primary to secondary eclipse of GG Orionis from 2018–2019 to 2025–2026 sci:sha256:37219a9fe1143fc78e84873e4270ce08af6db11b8b9156c314ca6cc6e22ce82b
[Legacy relation: reproduces] Our independent spline analysis reproduces the decrease in GG Orionis eclipse spacing between the same TESS visits. That detection preceded this study.
- usesTESS data show a 275 s decrease in the interval from primary to secondary eclipse of GG Orionis from 2018–2019 to 2025–2026 sci:sha256:37219a9fe1143fc78e84873e4270ce08af6db11b8b9156c314ca6cc6e22ce82b
We reuse the two unchanged JPL Horizons response files and preserve their original provenance and hashes. We do not reuse its source code.
- supportsA fixed CCD model predicts QLP minus SPOC times within 0.05 seconds in 128 stars from TESS sectors 90–97 sci:sha256:0ecf2f50171f780a08daabcc666f460f94c2a4f3bd68ff4b23de86b197285cf2
The prior fixed CCD rule predicts 1.96 seconds for CCD 2. All 24,162 Sector 98 QLP minus geometric target time differences agree within 0.003330 seconds. The new comparator is a geometric target correction, not a Sector 98 SPOC file.
- usesdoi:10.1051/0004-6361/202040004
We use the reference period and the published primary-secondary period difference for a comparison prediction.
- supportsdoi:10.1086/316855
This study established the eccentric binary orbit and measured its rotation before the TESS observations.
- usesdoi:10.1117/1.JATIS.1.1.014003
The input observations come from the TESS mission.
- usesdoi:10.1117/12.2233418
The Sector 6 input is the public mission SPOC light curve.
- usesdoi:10.17909/t9-r086-e880
The Sector 98 QLP light curve is a primary input.
- usesdoi:10.17909/t9-9j8c-7d30
The Sector 98 QLP product uses TICA calibration. We preserve the calibration metadata.
- usesdoi:10.48550/arXiv.2011.06459
This work describes the QLP methods used to produce the input light curve.
Cited by
2 publicationsPublic catalog entries on Sciscape.
- The QLP small aperture to image depth ratio increases by 38% between two GG Orionis secondary eclipses in TESS Sector 98
This prior study used the same GG Orionis observations to test eclipse times and time coordinates. We report a separate depth comparison.
- Half-depth widths do not clearly separate two orbit models at fixed stellar geometry in 17 TESS eclipses of GG Orionis
This earlier study tests time-coordinate effects for the later eclipses.