DOI: 10.5281/zenodo.17609914
title: 3I/ATLAS Photometric–Chromatic Anomaly (2025)
title: Optical Acceleration and Multi-Observatory Validation

description: 3I/ATLAS (C/2025 N1) Photometric–Chromatic Anomaly: Optical Acceleration and Multi-Observatory Validation

Version 2.4 — Extended Photometry and Post-Perihelion Deceleration



This dataset provides a fully updated, timestamped record of the 2025 photometric–chromatic evolution of the interstellar object 3I/ATLAS (C/2025 N1), extending MPC photometry through 2025-11-13 (4,413 observations). Using an optical activity proxy derived from the time derivative of the inverse magnitude, this work identifies:





A revised pre-perihelion optical activity peak on 2025-10-02,




A coincident reddening phase in the g−o colour index (+0.7 mag, July–Sept),




A post-perihelion deceleration and fading phase (early November),




No post-perihelion tail or fragmentation signatures in independent Nordic Optical Telescope (NOT) imaging.



What’s new in v2.4:





=== Data ===• MPC photometry updated through 13 Nov 2025• Clean parsing of all 4,413 records• Fixed duplicate-handling and run-log consistency




=== Analysis ===• Updated pre-perihelion peak timing• Improved post-perihelion acceleration reversal analysis• Updated plots: acceleration v2, post-perihelion evolution




=== Documentation ===• Revised paper with new figures and NOT morphological constraints• Corrected pipeline scripts (update_I3_data.sh, append_run_log_v3.sh)




=== Verification ===• Full OpenTimestamps Bitcoin proofs• GPG signatures• Complete proof bundle with manifests and hashes



This release supersedes v2.3 and provides the most temporally complete account of the optical evolution of 3I/ATLAS during its 2025 passage.


Key Contents:



Extended MPC photometry: 4,413 observations (2025-05-08 to 2025-11-13)

Optical acceleration proxy: Temporal derivative analysis revealing pre-perihelion peak (2025-10-02) and post-perihelion fading

Color evolution analysis: Strong reddening in g-o index (Δ ≈ +0.7 mag) during activity rise

Multi-observatory validation: NOT images showing compact morphology without cometary features

Complete research paper: "Photometric and Non-Gravitational Anomalies in 3I/ATLAS" with full methodology

Reproducible pipeline: Python scripts, verification proofs, and cryptographic timestamps
description: 🧩 Files Included








Category
Description




I3_ATLAS_v2_4_Analysis.pdf
Main analytical report (figures, tables, spectral and post-perihelion plots)


data/
Cleaned and calibrated photometric time-series (CSV)


scripts/
Python routines for spectral fit, colour-index computation, and anomaly quantification


proof_bundle/
Cryptographic verification materials: .sha256, .asc, .ots manifests
description: 🧠 Scientific Context

This work demonstrates that photometric monitoring can detect non-gravitational acceleration weeks before orbital solutions, providing early anomaly detection for interstellar objects. The optical acceleration proxy offers a low-cost, reproducible method complementary to dynamical analyses.
description: 🔐 Verification and Reproducibility

All analytical assets are timestamped, hashed, and digitally signed.The protect_atlas_v2_4.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_4.txt
The document itself


manifest_v2_4.txt.sha256
Integrity/authenticity hash


manifest_v2_4.txt.asc
GPG signature: proves authorship


manifest_v2_4.txt.ots
Bitcoin timestamp: proves date
description: 📚 Suggested Citation



Gherbi, Salah-Eddin (2025).3I/ATLAS (C/2025 N1) — Optical Acceleration and Multi-Observatory Validation: Extended Photometry and Post-Perihelion Deceleration (v2.4).Zenodo. https://doi.org/10.5281/zenodo.17609914
description: 🪶 Project Metadata

Project: 3I/ATLAS Photometric–Chromatic Anomaly Series (Independent Research Project, 2025 – ongoing)Author: Salah-Eddin Gherbi (Independent Researcher)Protection Pipeline: protect_atlas_v2_4.sh — reproducible cryptographic archival (SHA256 + OTS + GPG).Previous Release: v2.3 — Empirical Baseline & Reproducibility FrameworkLicense: CC BY-NC-SA 4.0
description: Version 2.4 – Extended Photometry and Post-Perihelion Deceleration

This release updates the 3I/ATLAS dataset with MPC photometry through 2025-11-13 (4,413 observations).It includes a revised timing of the pre-perihelion activity peak (2025-10-02) and a refined post-perihelion deceleration phase, captured through the updated optical activity proxy.

New additions in v2.4:





Updated MPC data (May–Nov 2025)




Revised optical activity peak (early October)




Improved post-perihelion fading analysis




Updated figures: optical acceleration v2, colour correlation (post-perihelion)




Full paper updated accordingly, including new morphological constraints from NOT imaging




Updated scripts and corrected logging pipeline (append_run_log_v3.sh)




Full cryptographic sealing (OpenTimestamps + GPG) with manifest



This version supersedes v2.3 and provides the most complete photometric–chromatic record of the 3I/ATLAS 2025 apparition.