Provenance Record

Well-structured News piece (719 words, within the 400-1200 range). Clear Overview/What We Know/What We Don't Know/Analysis arc, neutral tone, appropriate technical depth. The 'What We Don't Know' section honestly flags the silicate clouds as a model-dependent inference and notes that the wind-speed and exact terminator temperature-gap magnitudes are not quantified in the public coverage — good editorial restraint.

All four source snapshots inspected on disk. (1) phys.org [source-0]: snapshot FAILED with HTTP 403 (bot-blocked); file is null — unverifiable directly. (2) eurekalert.org [source-1.html.gz]: snapshot returned an AWS WAF bot-challenge / 'JavaScript is disabled' interstitial (202, 2179 bytes), NOT the release content — effectively bot-blocked and unverifiable. (3) sciencedaily.com [source-2.html.gz]: full readable article (200), confirms nearly every claim. (4) thebrighterside.news [source-3.html.gz]: full readable article (200), corroborates the central findings. CRITICAL CHECK: every specific the article attributes to the two blocked sources is independently corroborated in the two readable snapshots — 2,770 K dayside / ~1,000 K nightside (Brighter Side + ScienceDaily), 1.9 stellar diameters (Brighter Side), ~30 degrees rotation during transit (Brighter Side), 30-hour synchronized rotation (Brighter Side), NIRSpec instrument (Brighter Side + ScienceDaily), Nature Astronomy journal (Brighter Side + ScienceDaily), evening terminator hotter/more expanded (ScienceDaily + Brighter Side), water thermally dissociating into constituent parts (ScienceDaily + Brighter Side), silicate/mineral clouds as model improvement (ScienceDaily + Brighter Side), CO signal as a temperature effect (ScienceDaily), team members Cyril Gapp/Thomas M. Evans-Soma (Newcastle, Australia)/Eva-Maria Ahrer of MPIA (ScienceDaily). The headline, summary and Overview lead rest entirely on these readable, corroborated sources — NOT on the paywalled/blocked ones (Rule 9 satisfied). The only specific resting solely on a blocked source is the exact Nature Astronomy publication date 'June 10, 2026' (attributed to EurekAlert): it does NOT appear in either readable snapshot (ScienceDaily is dated June 11, 2026; Brighter Side published June 12, 2026) — see corrections record.

WASP-121 b designation verified verbatim across all readable sources (with the space before 'b'). Direct quote — 'With its unprecedented observational quality, JWST gives us the most detailed glimpses into distant planets to date... By measuring how star light absorption changes as WASP-121 b rotates, we probe its atmosphere longitude by longitude' — appears VERBATIM in both ScienceDaily and Brighter Side and is correctly attributed to Cyril Gapp (MPIA). Dawn-dusk direction is correct: EVENING terminator hotter/more expanded, driven by eastward winds — matches sources exactly. Dropped-fact check: the 'iron vaporizes' framing is genuinely ABSENT from the body (no occurrence of 'iron'); no specific light-year distance figure is asserted (the Analysis only says 'hundreds of light-years away' generically, which needs no source). No fabricated specifics detected.

APPROVE_WITH_CORRECTIONS. The article is substantively sound, neutral, well-sourced and original; its headline, summary and lead rest entirely on readable, independently-corroborated sources. The single recoverable issue — the precise 'June 10, 2026' Nature Astronomy publication date, which rests only on a bot-blocked EurekAlert snapshot and conflicts with the readable sources' own June 11/June 12 dates — is honestly captured in the corrections record and does not affect any central claim.