3I/ATLAS Photometric–Chromatic Anomaly (2025)

3I/ATLAS Photometric–Chromatic Anomaly (2025): Automated Peak Detection, Δv Correction, Ni/Fe Integration & Station-Consistency Validation (Version 2.6) Version 2.6 provides the most complete and internally consistent analysis to date of the photometric, chromatic, and dynamical behaviour of the interstellar object 3I/ATLAS (C/2025 N1). This release extends the MPC photometry through 2025-12-01 (4,960 lines total), incorporates newly available Gemini/GMOS and VLT/UVES spectroscopy, and introduces a fully automated, data-driven optical-acceleration and Δv reconstruction pipeline. Major scientific updates include (i) automated detection of optical-acceleration peaks, removing the need for manual timing, (ii) corrected Δv timing and amplitudes, (iii) integration of the reported Ni/Fe enrichment into the Interstellar Anomaly Index (IAI) via the new compositional axis Aₓ and (iv) a comprehensive station-by-station, time-normalised consistency test to evaluate whether late-November photometric deviations represent a genuine third activation episode. The new station-level analysis demonstrates that both late-November windows (Nov 22–25 and Nov 28–Dec 1) lack the multi-station coherence required of physical non-gravitational events. The apparent bumps observed in daily aggregation are therefore classified as photometric noise, not dynamical signals, and are excluded from the Δv budget and anomaly classification. This version includes all updated figures, Δv diagnostics, colour-correlation plots, brightness-timeline visualisations, station-consistency diagrams, and Python analysis scripts. All data products and code are authenticated by SHA-256 digests, GPG signatures, and OpenTimestamps Bitcoin proofs, maintaining a forensic-grade reproducibility chain. This release supersedes v2.5 and should be cited when referencing automated peak detection, corrected Δv timing, expanded compositional analysis, and post-perihelion station-consistency validation. 🔍 Overview of Version 2.6 Version 2.6 is the most automated, statistically rigorous, and spectroscopically integrated release of the 3I/ATLAS investigation to date. It includes: MPC photometry extended through 2025-12-01 (4,960 total lines) Automated peak detection for optical acceleration Corrected Δv timing and re-generated dynamical impulse curves Updated post-perihelion fading analysis through Dec 1 Complete colour–brightness timeline, including sharp $g$-band fading Spectroscopic anomaly integration via Ni/Fe ($A_x$) Expanded Interstellar Anomaly Index (IAI) New station-by-station, time-normalised consistency test Rejection of both late-November features as photometric noise All files, figures, and pipelines remain cryptographically timestamped (SHA-256, GPG, OpenTimestamps), maintaining full reproducibility. 📘 Manuscript The full updated LaTeX source and compiled PDF of “3I/ATLAS (C/2025 N1): Photometric and Non-Gravitational Anomalies in the Interstellar Object 3I/ATLAS (C/2025 N1)” are included. 🔐 Cryptographic Proofs All analysis files, scripts, and outputs are authenticated via: SHA-256 digests GPG signatures OpenTimestamps proofs anchored on the Bitcoin blockchain A reproducible “protect & seal” pipeline Ensuring full forensic reproducibility of the analysis chain.