J1407 data reject 59.56% of 14–17 year periods for a 30 day eclipse core if depth ≥0.5 mag, unobscured V ≥12.1, and calibration error ≤0.10 mag

A repeat of the 2007 J1407 eclipse was expected to be most likely in 2021–2024 in an earlier study. We test constant periods with public AAVSO Johnson V data retrieved on 2026-10-23. The test uses 6,071 quality-selected measurements from observer Franz-Josef (Josch) Hambsch in 2,763 nights from 2012 to 2026. The model repeats a 30 day core from MJD 54204 to 54234, with depth at least 0.5 magnitude and an epoch shift of up to one day. It assumes unobscured true V ≥12.1, absolute calibration error ≤0.10 magnitude, and a measurement-error allowance of five times each reported formal error. Two bright nights must conflict with the same repeat for every allowed epoch shift. Exact interval unions reject 652.627216 days of period length, or 59.56% of the full 14–17 year range. They reject 63.43% of the 16.5–17 year range and 61.80% of the 5–20 year range. The 2021–2024 data supply the new constraints in the main range. No 2026 night passes the primary brightness rule. The result depends strongly on assumed bounds: a 0.15 magnitude calibration bound gives 5.97% rejection, and an unobscured bound of V ≥12.0 gives zero rejection from 14 to 17 years. These are conditional exclusions, not orbital probabilities or a planet detection. We preserve fixed night summaries, source identifiers and hashes, original code, figures, sensitivity tests, and source-night evidence for all rejected intervals. Offline numerical reproduction and source extraction checks pass.

J1407 · V1400 Cen · repeat eclipses · period constraints · AAVSO · photometry · exoplanet candidates · reproducible research