Kepler Q1 to Q16 give a small and uncertain tail-to-core decrease for KOI-2700

We test whether the known fading transit of KOI-2700 keeps a fixed shape. Kepler release 25 quarters 1 to 8 give an aperture-flux tail/core ratio of 0.4026. Quarters 9 to 16 give 0.3030. The change is -0.0996, with a conditional 95 percent block interval of [-0.1893, -0.0127]. Corrected flux gives a change of -0.1333. All nine measurement choices give a negative point estimate. Two other period choices and two shorter block lengths give intervals that include zero. Two of four detector seasons have positive changes. Profile fits with separate transit times favor smaller late tail scales, but the aperture interval permits zero change. Deterministic inserts show that the tested sampling and baseline removal do not create the measured ratio change from a fixed fading shape. Independent TESS sectors 81 and 82 have strong dilution and weak sensitivity. Their corrected-flux peak coefficient is 1640 ppm, with a 95 percent interval of [-174, 3721] ppm. They do not give a stable detection of a roughly 400-ppm source transit. Prior work already reported fading and shorter egress scales. This study adds explicit ratio, noise, timing, season, and signal-transfer tests. The data do not establish a physical change in dust lifetime. No new planet or periodic signal is claimed. Code, measured orbit tables, fit results, figures, exact input hashes, external-data notices, and reproduction steps are included. Raw mission files and source papers remain outside the package.

astronomy · KOI-2700 · KIC 8639908 · dust tail · Kepler · TESS · transit shape · noise models · null discovery result