Provenance Record

Well-structured News piece (764 words, within the 400-1200 News range). Clear Overview / What We Know / What We Don't Know / Analysis arc. Technical depth (deuterium-to-hydrogen ratio as a frozen-in formation fingerprint, carbon-13 enrichment over galactic time) is explained accessibly without overreaching.

All 4 source snapshots read from disk and verified (gunzipped). source-0 (NASA Science, 200): confirms 'NIRSpec revealed exceptionally high levels of deuterium, about 30 times more than seen in solar system comets' verbatim, the Cordiner quote verbatim with correct attribution (astro-chemist, NASA Goddard, Greenbelt MD, lead author), 'began moving away from the Sun in December 2025', and NIRSpec detection of water/CO2/CO. source-1 (ESA, 200): confirms 'showed only traces of carbon-13 compared to lighter-weight carbon-12' verbatim, 'began moving away from the Sun in December 2025' verbatim, and paper 'published on 22 June 2026 in the journal Nature'. source-2 (EarthSky, 200): confirms '10 to 12 billion years ago, during the universe's cosmic noon, when star formation was at its height' verbatim and the Milam quote verbatim. source-3 (Sci.News, 200): confirms 'The abundance of heavy water shows that 3I/ATLAS spent its formative years in a deeply frozen state' verbatim and 'Cyrielle Opitom of the University of Edinburgh ... UV-Visual Echelle Spectrograph (UVES) on ESO's Very Large Telescope between December 6 and 26, 2025' verbatim. No WebFetch fallback needed; all snapshots returned 200.

Every specific traces to a cited fetchable source: deuterium ~30x (NASA/ESA), traces of carbon-13 vs carbon-12 (ESA/NASA), 10-12 Gyr age and 'cosmic noon' (EarthSky/NASA/ESA), Dec 2025 timing (NASA/ESA), VLT/UVES Opitom Dec 6-26 2025 (Sci.News). Rule 9 satisfied: the Nature paper (DOI 10.1038/s41586-026-10771-6) is deliberately NOT in the sources array and NO substantive claim rests on it; the only mention is the publication fact ('published June 22 in the journal Nature'), which is itself carried verbatim by the NASA and ESA snapshots. The article's '4.6 billion years ago' for the solar system vs the sources' '4.5 billion' is hedged with 'roughly' and is uncontroversial common knowledge.

APPROVE. Accurate, neutral, appropriately hedged interstellar-comet follow-up. All four cited sources personally read and confirm every quote, number, name and date. No claim rests on the cookie-walled Nature paper. No orphan URLs (all 4 body URLs are in article.sources). The script's APPROVE_WITH_CORRECTIONS default was driven solely by the non-blocking allowlist warning, which is not a correctable factual error; verdict set to APPROVE with no corrections record.