KIC 4544587 eclipse gaps from 2009–2024 fit an apsidal rate near 27 mrad/year if eccentricity is constant and centers trace conjunctions
Kepler and TESS eclipse gaps test a common orbit model for KIC 4544587 from 2009 to 2024. We measure symmetric eclipse cores in public source data. We fit exact projected conjunctions with constant eccentricity and constant forward rotation at inclination 87.9 degrees. The fitted rate is near 27 milliradians per year. This rate assumes that the measured centers trace geometric conjunctions. We test the published rate of 42.97 milliradians per year after we fit eccentricity and orientation again. It leaves residuals of several minutes. Core width, flux correction, data flags, and short cadence checks retain the lower rate. At the fixed rate, the bound on all center errors must be at least about 204 seconds in the tested parameter box. We preserve 38 original FITS files, query records, hashes, timing tables, source code, figures, and run instructions. This extends a prior SCI TESS study to the earlier Kepler data. It does not establish a physical rate, a planet, or a unique cause for the difference. Stellar pulsations, brightness asymmetry, and other center biases need a full physical model.
KIC 4544587 · eclipsing binary · apsidal motion · Kepler · TESS · eclipse timing · timing bias · reproducible data
References
9- usesThe 2019–2024 TESS gaps of KIC 4544587 exceed the fixed ellipse limit for eccentricity 0.252 at inclination 87.9° if centers trace conjunctions sci:sha256:c1ab2c84bee76752cbba6e59942ac1fddefdc78dcfc4e9f62bb897963274f388
We reuse seven unchanged TESS source files and their query and provenance records. We extend its TESS-only gap and rate tests with Kepler data, new timing fits, a short cadence check, and a timing bias test.
- challengesdoi:10.3847/1538-4357/ac22b0
We test the stated total rate of 42.97 mrad/year across 2009–2024 with exact conjunctions after we refit eccentricity and orientation. The result applies to a constant eccentricity orbit if symmetric eclipse centers trace geometric conjunctions. We do not refit the complete stellar or tidal model.
- doi:10.1093/mnras/stt886
This work gives the earlier physical orbit, pulsations, and apsidal motion context. It supplies the adopted inclination.
- usesdoi:10.17909/T9RP4V
We use 18 public Kepler long cadence and 13 short cadence source light curves. Exact product names and source hashes are preserved.
- usesdoi:10.17909/T9-NMC8-F686
We use seven public TESS two-minute light curves, with exact products and hashes preserved.
- usesdoi:10.1038/s41586-020-2649-2
We use NumPy for array calculations and the fixed random generator.
- usesdoi:10.1038/s41592-019-0686-2
We use SciPy for eclipse timing, least squares, constrained optimization, and the independent optimizer check.
- usesdoi:10.3847/1538-4357/ac7c74
We use Astropy to read the source FITS files and convert times.
- usesdoi:10.1109/MCSE.2007.55
We use Matplotlib to make the result figures.
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