DOI: 10.5281/zenodo.17793630
title: 3I/ATLAS Photometric–Chromatic Anomaly (2025)
title: Automated Peak Detection, Δv Correction, and Station-Consistency Validation

description: 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.
description: Version Summary

This version introduces automated peak detection for optical acceleration, corrected Δv timing, and a new station-level consistency test for evaluating late-November photometric deviations. The MPC dataset is now extended through 2025-12-01, and Δv(t) reconstructions, acceleration plots, and IAI components have been regenerated accordingly. Newly published UVES spectroscopy is incorporated via a compositional anomaly axis (Aₓ) based on Ni/Fe enrichment, expanding the Interstellar Anomaly Index. Station-by-station validation confirms that the November 22–25 and November 28–December 1 features are noise rather than physical acceleration events. All data products, figures, and analysis scripts are cryptographically timestamped for full reproducibility.
description: 🧾 Version 2.6 Detailed Notes (Fully Expanded)

Major Improvements





Automated optical peak detection




Corrected Δv timing




New colour–brightness timeline




Updated post-perihelion fading analysis (to Dec 1)




Station-level consistency tests (two windows)




Ni/Fe anomaly integrated into IAI




Regenerated Δv figures, including overlays




New figures for station-level noise discrimination




All scripts updated for auto-detection of colour files




Manifest updated with all new files + integrity proofs



Data Coverage





Observations: 4,960 MPC records




Time span: 2025-05-08 → 2025-12-01




Nights with valid photometry: ≈ 130




Multi-filter colour coverage: 2025-07-01 → 2025-09-11



Noise Assessment

The two apparent late-November bumps are now conclusively identified as noise, based on:





29 independent stations




No >3σ coherent deviations




Mixed signs across stations




Weak daily means (0.0266×10⁻³ and 0.0004×10⁻³)




Second bump dominated by a single observatory



Forensic Reproducibility

All outputs are sealed using:





SHA-256 checksums




GPG signatures




OpenTimestamps (Bitcoin)
description: 🧩 Files Included (v2.6)

A fully updated table reflecting the structure of this version.








Category
Description (Updated v2.6)




I3_ATLAS_v2_6_Analysis.pdf
Full analytical report including: automated peak detection results, corrected Δv timing, extended post-perihelion fading, colour–brightness timeline, Ni/Fe compositional anomaly, IAI components, Δv overlays, and station-consistency diagnostics.


data/
Cleaned & derived data products:• I3.txt — MPC photometry through 2025-12-01• I3_Optical_Acceleration_Data.csv — full optical-acceleration time series• I3_Color_Alerts_*.csv — auto-selected colour windows• Colour statistics, monthly means, brightness timelines


figures/
All scientific figures generated in v2.6:• Optical acceleration (trend + peaks)• Colour–acceleration correlation (pre-perihelion)• Post-perihelion optical evolution• Δv impulse curves (8 m/s & 25 m/s)• Δv overlays & cumulative curves• Station-consistency plots (two November windows)• IAI component radar diagram• Eccentricity–IAI plane positioning• Colour–brightness timeline figure


scripts/
Complete Python analysis suite:• Automated optical-acceleration extraction• Δv modelling (single & dual-scaling)• Peak detection utilities• Colour-index pipelines• IAI component computation• Station-consistency evaluationAll scripts are reproducible and version-controlled.


proof_bundle/
Full cryptographic provenance:• SHA-256 manifests (manifest_v2_6.txt, *.sha256)• GPG signatures (*.asc)• OpenTimestamps proofs (*.ots)Ensures forensic-grade verification of the entire scientific workflow.
description: 🧪 2. Scientific Context — Updated for v2.6

A polished, stronger, and fully accurate version reflecting the expanded dataset.

The photometric–chromatic anomaly framework developed in previous releases demonstrated that photometry alone can reveal dynamical precursors—changes in brightening rate and colour evolution—before orbital astrometry reflects non-gravitational acceleration.

Version 2.6 expands this framework significantly.

What v2.6 reveals:





The optical-acceleration proxy continues to provide a precise chronology of activation:





two sharp pre-perihelion spikes (Sept 9 and Oct 2),




followed by a monotonic post-perihelion decline.






Automated peak detection removes subjective human timing.




Δv reconstruction confirms that these short-lived impulses dominate the momentum budget (90–95% of Δv).




The colour–brightness timeline shows a clean transition to fading, with +1.5 mag dimming in the g-band.




UVES spectroscopy introduces Ni/Fe overabundance, enabling a new compositional anomaly axis AxA_xAx.



Novel capability introduced in v2.6

The station-by-station, time-normalised validation is a major methodological advance:





It distinguishes real physical acceleration from artefacts by checking:✔ coherence across telescopes✔ sign consistency✔ amplitude significance✔ temporal clustering




Both late-November features fail these tests:





Nov 22–25: appears coherent in aggregation but not in station signals.




Nov 28–Dec 1: dominated by a single station (703), not physical.





Thus no third activation event is detected beyond the two major pre-perihelion impulses.

Scientific impact

Version 2.6 establishes that:





Photometric anomaly analysis is a robust early-warning tool for interstellar objects.




Δv estimates derived purely from photometry can match dynamical requirements (e.g., Loeb’s Jupiter geometry).




The Interstellar Anomaly Index provides a multi-axial classification across photometric, chromatic, dynamical, morphological, and compositional domains.




The Ni/Fe anomaly integrates compositional spectroscopy into the anomaly-scoring framework for the first time.




Noise discrimination using multi-station analysis becomes essential for interpreting faint post-perihelion signatures.



This combination of methods—photometry, colour indices, Δv reconstruction, anomaly quantification, and station-consistency analysis—constitutes a reproducible, instrument-independent system for assessing interstellar-object behaviour.
description: 🔐 Verification and Reproducibility

All analytical assets are timestamped, hashed, and digitally signed.The protect_atlas_v2_6.sh script generates a deterministic proof bundle containing:





SHA-256 integrity manifest




GPG signature (.asc)




OpenTimestamps blockchain proof (.ots)



These provide verifiable provenance and cryptographic reproducibility for all datasets, figures, and analysis scripts.

Check folder manifests with the files:




Manifest File
Purpose




manifest_v2_6.txt
The document itself


manifest_v2_6.txt.sha256
Integrity/authenticity hash


manifest_v2_6.txt.asc
GPG signature: proves authorship


manifest_v2_6.txt.ots
Bitcoin timestamp: proves date
description: 📚 Suggested Citation



Gherbi, Salah-Eddin (2025).3I/ATLAS (C/2025 N1) — ATLAS Photometric–Chromatic Anomaly (2025): Automated Peak Detection, Δv Correction, and Station-Consistency Validation (v2.6).Zenodo. https://doi.org/10.5281/zenodo.17793630
description: 🪶 Project Metadata

Project: 3I/ATLAS Photometric–Chromatic Anomaly SeriesScope: Independent research programme (2025 – ongoing) focused on photometric, chromatic, and dynamical diagnostics of the interstellar object 3I/ATLAS (C/2025 N1).

Author: Salah-Eddin GherbiIndependent researcher — photometry, interstellar object analysis, planetary dynamics, anomaly quantification.

Reproducibility Pipeline:protect_atlas_v2_6.sh — automated archival and authentication pipeline using:





SHA-256 manifests




GPG detached signatures




OpenTimestamps (Bitcoin-anchored) proofsensuring full temporal integrity and verifiable provenance of the dataset.



Previous Release:v2.5 — Δv-based dynamical modelling, Interstellar Anomaly Index (IAI), extended post-perihelion evolution.

Current Release:v2.6 — Automated Peak Detection, Δv Correction, Ni/Fe Integration & Station-Consistency Validation, extended post-perihelion evolution, updated manuscript, complete pipeline and proof bundle.

License: CC BY-NC-SA 4.0Open for non-commercial use with attribution; derivatives permitted under identical terms.