{
  "abstract": "Near-ultraviolet imaging of the planet Venus reveals inhomogeneous absorption features in the otherwise bright clouds. This absorption has been studied for nearly 100 years, but identification of the near-UV absorber remains one of the largest open questions in Venusian research. Based on a multiple scattering radiative transfer model, the observed absorption between 300 and 600 nm can be produced by 1.0-1.2 wt% ferric chloride (FeCl 3 ) in the mode 1 (∼0.2 μm radius) sulfuric acid cloud droplets-less than the in-cloud iron mass loading measured during the Venera-12 mission. We present a novel chemical network within a global chemistry-climate model, which provides the required source of FeCl 3 in the upper cloud region from the reaction of Fe-containing molecules, produced by the ablation of cosmic dust particles, with atmospheric HCl. A residence lifetime of ∼3,000 years is required to provide sufficient optical absorption from a purely meteoric source of FeCl 3 . Iron chloride has been proposed to cause the strong absorption seen in Venus's clouds. Using computer modeling of light in the atmosphere, we test the effect of iron chloride in the droplets that make up the Venusian clouds. We find that a modest concentration of 1.0%-1.2% (by mass) in the smallest cloud droplets can reproduce the shape and strength of the absorption recorded by the MESSENGER spacecraft. We present chemical reactions that produce iron chloride from the reaction of atmospheric hydrochloric acid gas and iron atoms produced from vaporized cosmic dust, and estimate that the iron chloride would take approximately 3,000 years to concentrate enough to match observations of the clouds.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "name": "Joanna V Egan"
    },
    {
      "name": "Wuhu Feng"
    },
    {
      "name": "Alexander D James"
    },
    {
      "name": "James Manners"
    },
    {
      "name": "Daniel R Marsh"
    },
    {
      "name": "Sébastien Lebonnois"
    },
    {
      "name": "Franck Lefèvre"
    },
    {
      "name": "Aurélien Stolzenbach"
    },
    {
      "name": "John M C Plane"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4hmrfa3kjk74p.bib",
  "cited_by": 0,
  "doi": "10.1029/2025je009634",
  "fulltext_url": null,
  "id": "4hmrfa3kjk74p",
  "issns": [
    "2169-9097",
    "2169-9100"
  ],
  "landing_url": "https://hal.science/hal-05752314v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdu"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://hal.science/hal-05752314/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-16",
  "publisher": "Wiley-Blackwell",
  "ris": "https://research.draconitic.com/paper/4hmrfa3kjk74p.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:35Z",
      "native_id": "hal-05752314",
      "source": "hal",
      "url": "https://hal.science/hal-05752314v1"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "journal-openalex:3103|Astro and Planetary Science",
      "subfield": "planetary"
    }
  ],
  "title": "Ferric Chloride: The Venusian Unknown UV Absorber?",
  "title_text": "Ferric Chloride: The Venusian Unknown UV Absorber?",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:35Z",
  "url": "https://research.draconitic.com/paper/4hmrfa3kjk74p",
  "venue": "Journal of Geophysical Research. Planets",
  "versions": []
}