Target times reduce the DD CrB timing contrast by 14.45 seconds in symmetric fits to five TESS sectors

We test the time convention in a paired eclipse analysis of DD CrB, also called NSVS 07826147 and TIC 148785530. We use TESS sectors 24, 50, 51, 77, and 78 from 2020, 2022, and 2024. Symmetric, exposure-averaged profiles use 439 primary and 445 secondary eclipses. A three-season common contrast is 16.81 seconds when the 2024 TESScut times are used as target times. Those times have a barycentric correction for the CCD center. Replacing that correction with the target correction reduces the contrast by 14.45 seconds, to 2.36 seconds. The conditional standard error is 0.96 seconds from paired two-day block deletions. The secondary-minus-primary contrast is 0.46 plus or minus 1.98 seconds. Across 14,155 matched exposures, a fixed CCD rule from prior work predicts the remaining QLP-minus-target offset within 0.11 milliseconds. This checks relative time conventions, not absolute clock accuracy. An aligned pipeline-flux control gives a common contrast of 1.06 seconds. The remaining signal depends on flux processing and profile assumptions. We do not establish a planet or test the published 2026 companion fit independently. Repeated downloads reproduce unresolved SPOC extension checksum failures. The package preserves these files, source hashes, code, controls, figures, and an offline reproduction.

DD CrB · NSVS 07826147 · TIC 148785530 · TESS · TESScut · QLP · eclipse timing · barycentric correction · time conventions · reproducible astronomy

Admitted 2026-11-09 18:51 UTC1 citing publication

References

usesSymmetric eclipse fits show a shared 18 s departure in NY Vir TESS sector 91 from the line through sectors 23 and 50 sci:sha256:27b21c0322f367cb77dd5de188a0263813889acfbe0c8c05fdf1771a37dae920
This study supplies prior examples of paired eclipse clocks and a contrast that cancels a linear clock. We implement the approach independently for DD CrB.
usesSymmetric TESS fits give a 2022 to 2024 interval 28 seconds longer than the 2025 quadratic clock for NSVS 14256825 sci:sha256:2c0f59e955f8f27dd1f8a855590204c65f47947b7a46db99d359c1e2941edbe1
This study supplies prior examples of exposure-averaged spline fits, recovery checks, and source checksum checks. Our code is an independent implementation.
usesA fixed CCD and frame model predicts QLP minus TESS-SPOC times within 0.02 seconds in 96 sector 84–85 stars sci:sha256:889f137a5e470a7c5261ddf1f7db71148963c24a8593e8bd687dcc52832e5092
We use its fixed historical CCD midpoint rule without fitting an offset for this star. The rule predicts QLP minus our target-corrected times within 0.11 milliseconds in sectors 77 and 78.
doi:10.1093/mnras/stag290
This prior study uses all five TESS sectors for primary eclipse times and earlier sectors for the mean primary-secondary delay. It proposes a companion model. Our time audit does not independently test that model.
usesdoi:10.1093/mnras/staf1636
We use its reference epoch and period to assign binary cycles. It supplies prior evidence that later eclipse times do not follow an earlier companion prediction.
doi:10.1051/0004-6361/202039851
This prior study proposes a third-body explanation for DD CrB eclipse times.
doi:10.3847/1538-4357/aa6980
This prior study measures primary and secondary eclipses and discusses their relative time delay.
usesdoi:10.17909/t9-nmc8-f686
We use the preserved 120-second SPOC light curves for sectors 24, 50, and 51. The package records exact file names and hashes.
usesdoi:10.17909/t9-st5g-3177
We use the preserved 20-second SPOC light curves for sectors 50 and 51 as a cadence control.
usesdoi:10.17909/t9-r086-e880
We use version 02 QLP light curves for sectors 77 and 78 to check times and flux processing.

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Public catalog entries on Sciscape.

supportsSymmetric fits to three TESS sectors give a secondary eclipse delay of 2.16 ± 0.59 seconds in DD CrB
Earlier paired timing and time-convention work on this target gives consistent sector delays and reports the same unresolved SPOC extension checksum failures. We test mean-delay precision with additional information and recovery checks.