Fits with a uniform planet and circular stellar limb give shorter mean KELT-9 b secondary eclipse duration estimates in six TESS sectors from 2019 to 2024
We test whether secondary eclipses of KELT-9 b give a duration decrease in the six TESS sectors used by earlier primary transit studies. We fit 91 eclipses from 2019 to 2024. Each event has a free depth, local baseline, and stellar pulse terms. Each sector has a free duration and center. The model uses a uniform circular planet and a circular stellar limb. The mean duration in the two 2024 sectors minus the mean in the two 2019 sectors is -5.60 minutes. Resampling whole events within each sector gives a conditional 95% interval of -8.08 to -2.65 minutes. Thirteen changes to the fit model give point estimates from -5.71 to -4.81 minutes. However, the two 2019 sectors differ by 7.58 minutes. The smooth circular-star precession comparison predicts only about 0.04 minutes between those visits. The resampling does not include errors shared by a whole sector or year. A noiseless test with a different eclipse shape recovers an input change of -3.322 minutes as -4.053 minutes. Thus these data give a model duration decrease, but they do not establish its physical cause or give a new detection of precession. We supply the six source light curves, file hashes, code, event records, resample draws, recovery tests, figures, and offline repeat instructions.
KELT-9 b · TESS · secondary eclipse · eclipse duration · stellar pulsation · nodal precession · event bootstrap · reproducible astronomy
References
14- usesLocal fits to six TESS sectors do not resolve a KELT-9 b eclipse depth change from 2019 to 2024 sci:sha256:a6203af39c5839b4acca6c41bd66edb381d894a74311589743fb8b933c7f02a7
We reuse its six source FITS files, data provenance, event selection, local baseline structure, and adapted overlap code. That study kept eclipse duration fixed.
- usesFits with free brightness give shorter KELT-9 b contact duration estimates in six TESS sectors from 2019 to 2024 sci:sha256:dc3e8d9f484f38dd11e34f1fde84c6fd860a17f331ff2031bcb542fe73cc065b
We use its primary contact duration results and circular-star precession calculation as comparisons. We do not fit primary transits again.
- usesLocal fits to six TESS sectors show smaller KELT-9 b transit widths from 2019 to 2024 sci:sha256:d8ecadc9016b325bcfb3f4e32394b59c10aa069839676c80c12281461b07465d
This record supplied the original public data snapshot and archive request records through the cited eclipse study.
- usesdoi:10.17909/t9-nmc8-f686
NASA TESS and SPOC light curves from MAST supply the measurements. The package records exact product names and file hashes.
- doi:10.3847/1538-4357/ac6b9a
Stephan et al. already established nodal precession. Its orbital model underlies the copied circular-star comparison.
- usesdoi:10.3847/1538-3881/aba2cb
Wong et al. measured the stellar pulse and optical phase curve. The 7.58695-hour pulse period enters the local fits.
- usesdoi:10.1051/0004-6361/202243823
Jones et al. supply the reference shape parameters and an alternative pulse period. Their work also describes the effect of stellar variation and data reduction on eclipse and orbit estimates.
- doi:10.3847/1538-3881/ab8fa3
Ahlers et al. describe gravity darkening in this rapidly rotating star. A circular stellar limb limits the present physical interpretation.
- usesdoi:10.48550/arXiv.2602.01446
The source studies credit this work through TEPCat for the event-location clock. We retain that clock and fit sector eclipse centers.
- usesdoi:10.1086/683602
The independent synthetic eclipse generator uses batman.
- usesdoi:10.1038/s41586-020-2649-2
The analysis uses NumPy.
- usesdoi:10.1038/s41592-019-0686-2
The analysis uses SciPy.
- usesdoi:10.3847/1538-4357/ac7c74
The analysis uses Astropy.
- usesdoi:10.1109/MCSE.2007.55
The figures use Matplotlib.
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