{
  "abstract": "Interstellar objects (ISOs) provide direct constraints on the composition and evolution of extrasolar planetary systems. As the third confirmed ISO, comet 3I/ATLAS offers a rare opportunity to study pristine material from another star system. We present a systematic multiband monitoring campaign conducted from 2025 July to September. To minimize systematic uncertainties, we utilized a homogeneous dataset of Sloan Digital Sky Survey (SDSS) g ′ , r ′ , i ′ , z s and Johnson–Cousins BVR imaging obtained with MuSCAT3/4 on the 2.0 m Faulkes Telescopes and the 1.5 m Maidanak telescope. We employed a novel multiaperture technique that provides a robust, distance-independent characterization of the coma, alongside optical spectroscopy from SALT and the Nordic Optical Telescope. 3I/ATLAS exhibited a stable reddish color with no significant secular variation during its inbound journey. Spectroscopic analysis reveals carbon-chain depletion, with CN as the only prominent molecular emission. Coma morphology, analyzed via azimuthal averaging and rotational gradient filters, shows a persistent sunward jet at a position angle of ∼280 ∘ , indicating sustained and localized outgassing from a high-latitude active region. Modeling of light scattering demonstrates that the observed colors and polarization are consistent with dense aggregates of organic matter and silicate minerals, while water-ice sublimation remained insufficient to alter the optical properties. The stability of the coma structures and the homogeneous nature of our dataset indicate that 3I/ATLAS underwent a steady activation phase, preserving a volatile-rich but carbon-chain-poor composition. This characterization points to an object formed in a distinct protoplanetary environment and provides a definitive record of its pre-perihelion evolution.",
  "abstract_shown": true,
  "affiliations": [
    "Universidad de Alicante",
    "Universitat de Barcelona (UB)",
    "Université Côte d’Azur",
    "V.N. Karazin Kharkiv National University",
    "Astronomical Institute of the Slovak Academy of Sciences",
    "Main Astronomical Observatory of the National Academy of Sciences of Ukraine",
    "Adam Mickiewicz University",
    "Institut für Geophysik und Extraterrestrische Physik",
    "Astronomical Observatory of Taras Shevchenko National University of Kyiv",
    "University of Helsinki",
    "South African Astronomical Observatory",
    "Stellenbosch University",
    "Ulugh Beg Astronomical Institute",
    "Université PSL"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "T. Santana-Ros",
      "orcid": "0000-0002-0143-9440"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Alexey V. Sergeyev",
      "orcid": "0000-0003-3425-5178"
    },
    {
      "affs": [
        4,
        5
      ],
      "name": "Oleksandra V. Ivanova",
      "orcid": "0000-0001-7285-373X"
    },
    {
      "affs": [
        6
      ],
      "name": "Sofiia Mykhailova",
      "orcid": "0009-0000-1081-7944"
    },
    {
      "affs": [
        7
      ],
      "name": "Johannes Markkanen",
      "orcid": "0000-0001-5989-3630"
    },
    {
      "affs": [
        8
      ],
      "name": "Igor V. Luk'yanyk",
      "orcid": "0000-0002-3779-7864"
    },
    {
      "affs": [
        6
      ],
      "name": "T. Kwiatkowski",
      "orcid": "0000-0003-3462-5714"
    },
    {
      "affs": [
        6
      ],
      "name": "Dagmara Anna Oszkiewicz",
      "orcid": "0000-0002-5356-6433"
    },
    {
      "affs": [
        9
      ],
      "name": "Antti Penttilä",
      "orcid": "0000-0001-7403-1721"
    },
    {
      "affs": [
        10,
        11
      ],
      "name": "Nicolas Erasmus",
      "orcid": "0000-0002-9986-3898"
    },
    {
      "affs": [
        12
      ],
      "name": "K. E. Ergashev",
      "orcid": "0000-0002-7521-1078"
    },
    {
      "affs": [
        13,
        3
      ],
      "name": "Yu. N. Krugly",
      "orcid": "0000-0002-3171-9873"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3st0h6hzmm5vj.bib",
  "cited_by": 5,
  "doi": "10.3847/1538-4357/ae8dbb",
  "fulltext_url": null,
  "id": "3st0h6hzmm5vj",
  "issns": [
    "0004-637X",
    "1538-4357"
  ],
  "landing_url": "https://doi.org/10.3847/1538-4357/ae8dbb",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1912|Astro and Planetary Science"
    ]
  ],
  "openalex": "W7203713991",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae8dbb/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-18",
  "publisher": "IOP Publishing",
  "ris": "https://research.draconitic.com/paper/3st0h6hzmm5vj.ris",
  "sources": [
    {
      "first_seen": "2026-11-07T13:21:01Z",
      "native_id": "W7203713991",
      "source": "openalex",
      "url": "https://doi.org/10.3847/1538-4357/ae8dbb"
    }
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:1912|Astro and Planetary Science",
      "subfield": "planetary"
    }
  ],
  "title": "The Inbound Gas and Dust Evolution of Interstellar Comet 3I/ATLAS from Optical Spectroscopy and Multiband Photometry*",
  "title_text": "The Inbound Gas and Dust Evolution of Interstellar Comet 3I/ATLAS from Optical Spectroscopy and Multiband Photometry*",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T13:21:19Z",
  "url": "https://research.draconitic.com/paper/3st0h6hzmm5vj",
  "venue": "The Astrophysical Journal",
  "versions": []
}