{
  "$schema": "https://themachinepress.com/schemas/story-v1.schema.json",
  "schema_version": "1.0.0",
  "document_type": "machine_press_story",
  "story": {
    "story_id": "mp-2026-09-21-007",
    "source_story_id": "tmp-story-wasp52b-co2-water",
    "edition_id": "mp-2026-09-21-morning-0074",
    "edition_url": "https://themachinepress.com/edition/2026-09-21",
    "position": 7,
    "story_type": "dispatch",
    "section": "research",
    "editorial_classification": "editorial",
    "headline": "JWST Found Carbon Dioxide Under Spotty Starlight",
    "slug": "jwst-found-carbon-dioxide-under-spotty-starlight",
    "dek": "The hot Saturn’s spectrum also shows water, while starspots and clouds complicate its composition.",
    "summary": "The hot Saturn’s spectrum also shows water, while starspots and clouds complicate its composition.",
    "body_text": "JWST/NIRSpec transmission observations of WASP-52b yielded the first reported carbon-dioxide detection in that atmosphere and a confirmation of water. The team modeled unocculted starspots to explain a steep near-infrared slope and found suggestive evidence for uneven high-altitude clouds along the planet’s terminator. Composition remains uncertain because molecular abundances trade off against clouds and stellar contamination; different retrieval assumptions allow sub-solar through super-solar metallicity.",
    "why_it_matters": "The hot Saturn’s spectrum also shows water, while starspots and clouds complicate its composition.",
    "limitations": [],
    "importance": 8,
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-21-007/jwst-found-carbon-dioxide-under-spotty-starlight",
    "json_url": "https://themachinepress.com/story/mp-2026-09-21-007.json",
    "first_published_at": "2026-09-21T09:00:00.000-04:00",
    "modified_at": "2026-09-21T09:00:00.000-04:00",
    "content_status": "new",
    "is_carryover": false,
    "carryover_reason": null,
    "key_claims": [
      {
        "claim_id": "claim-mp-2026-09-21-007-001",
        "text": "The hot Saturn’s spectrum also shows water, while starspots and clouds complicate its composition.",
        "source_ids": [
          "source-2026-09-21-007"
        ],
        "qualification": null
      }
    ],
    "source_ids": [
      "source-2026-09-21-007"
    ],
    "tags": [
      "JWST",
      "exoplanet atmosphere",
      "WASP-52b"
    ],
    "image_url": null,
    "corrections": []
  },
  "sources": [
    {
      "source_id": "source-2026-09-21-007",
      "title": "arXiv preprint 2609.21810",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2609.21810",
      "canonical_url": "https://arxiv.org/abs/2609.21810",
      "source_type": "primary_research",
      "is_primary_source": true,
      "published_at": "2026-09-18T10:20:26.000-04:00",
      "accessed_at": "2026-09-21T08:26:05.112-04:00",
      "supports_claim_ids": [
        "claim-mp-2026-09-21-007-001"
      ]
    }
  ],
  "corrections": [],
  "publisher": {
    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
  },
  "cite_this_report": {
    "title": "JWST Found Carbon Dioxide Under Spotty Starlight",
    "publisher": "The Machine Press",
    "published_at": "2026-09-21T09:00:00.000-04:00",
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-21-007/jwst-found-carbon-dioxide-under-spotty-starlight"
  }
}