3I/ATLAS (C/2019 Y4) - Photometric Anomaly 2025

This version extends the original 3I/ATLAS (C/2019 Y4) Photometric Anomaly 2025 dataset with a comparative analysis against predicted magnitudes from NASA’s JPL Horizons ephemerides service.Observed photometric data from the Minor Planet Center (MPC) were cross-matched with modelled total magnitudes (Tmag) to quantify residual deviations using open-source Python scripts. The results confirm a sustained brightness excess of Δm ≈ 4.2 mag (≈ ×47 flux) during July–October 2025, significantly exceeding geometric illumination expectations.Residual analysis and normalized light-curve visualizations reinforce the interpretation of intrinsic physical activity—likely surface reactivation or volatile release—following the object’s solar conjunction. All new outputs (residual CSVs, normalized plots, and updated analysis scripts) are SHA-256 verified and timestamp-anchored on the Bitcoin blockchain via OpenTimestamps, ensuring permanent reproducibility and authenticity.