{
  "abstract": "We present a spatially contiguous spectroscopic analysis of the physical and chemical structure of the Helix Nebula (NGC 7293, PNG 036.1-57.1) using integral-field observations from the SDSS-V Local Volume Mapper (LVM). The nearly complete nebular coverage allows us to map extinction, electron density and temperature, ionisation structure, and chemical abundances within a common dataset. We reconstruct calibrated datacubes from the LVM row-stacked spectra and measure 41 optical emission lines from hydrogen, helium, and collisionally excited ions. The Helix is globally a low-density nebula, with characteristic electron densities of ∼102 cm−3, but shows a strongly structured thermal distribution. Te([O III]) exhibits a U-shaped radial profile, decreasing from the central cavity to intermediate radii and rising toward the outer nebula, while Te([N II]) increases outward and Te([O II]) decreases. These contrasting behaviours show that different diagnostics trace distinct ionisation zones. The spatially resolved abundance analysis yields a near-solar oxygen abundance, 12 + log (O/H) ≃ 8.7, consistent with an approximately chemically homogeneous nebula once ionisation structure is considered. Simulated long-slit extractions show that inferred O/H depends systematically on slit orientation and can remain biased after ionisation correction, demonstrating the importance of spatial coverage in strongly stratified nebulae. We also find sulfur systematically deficient relative to other α-elements, consistent with the planetary-nebula sulfur anomaly. These results highlight the power of wide-field integral-field spectroscopy for linking the thermal, ionisation, and chemical structure of extended planetary nebulae.",
  "abstract_shown": true,
  "affiliations": [
    "Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México , 58090 Morelia, Michoacán ,",
    "Universidad Nacional Autónoma de México. Instituto de Astronomía . A.P. 70-264, 04510. Ciudad de México ,",
    "Universidad Nacional Autónoma de México. Instituto de Astronomía . A.P. 106, 22800. Ensenada, B.C. ,",
    "Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México , Av. Universidad s/n, 62210 Cuernavaca, Morelos ,",
    "Instituto de Astrofísica de Canarias , Vía Láctea s/n, 38205, La Laguna, Tenerife ,",
    "Institute of Astrophysics, Facultad de Ciencias Exactas, Universidad Andrés Bello, Sede Concepción , Talcahuano ,",
    "Universidad de Chile Departamento de Astronomía, , Camino del Observatorio 1515, Las Condes, Santiago ,",
    "Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales , Av. Ejército Libertador 441, Santiago ,",
    "Universidad de La Serena Department of Astronomy, , Av. Raul Bitran 1302, La Serena ,",
    "University of Colorado , Boulder, CO 80309 ,",
    "Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg , Mönchhofstr. 12-14, D-69120 Heidelberg ,",
    "Universidad Nacional Autónoma de México , Facultad de Ciencias, Av. Universidad 3000, 04510, Cd. de",
    "University of Utah Department of Physics and Astronomy, , 270 S. 1400 E. #E2108, Salt Lake City, UT 84112 ,",
    "New York University Abu Dhabi , PO Box 129188, Abu Dhabi ,",
    "Center for Astrophysics and Space Science (CASS), New York University Abu Dhabi , PO Box 129188, Abu Dhabi ,",
    "Sternberg Astronomical Institute, Lomonosov Moscow State University , Universitetskij pr., 13, Moscow, 119234 ,",
    "Universidad de Chile , Av. Libertador Bernardo O’Higgins 1058 ,",
    "Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 29,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "R Orozco-Duarte"
    },
    {
      "affs": [
        1
      ],
      "name": "J E Méndez-Delgado"
    },
    {
      "affs": [
        0
      ],
      "name": "J A Toalá"
    },
    {
      "affs": [
        2
      ],
      "name": "L Sabin",
      "orcid": "0000-0003-0242-0044"
    },
    {
      "affs": [
        3
      ],
      "name": "C Morisset",
      "orcid": "0000-0001-5801-6724"
    },
    {
      "affs": [
        1,
        4
      ],
      "name": "S F Sánchez"
    },
    {
      "affs": [
        1
      ],
      "name": "H Ibarra-Medel"
    },
    {
      "affs": [
        0
      ],
      "name": "W J Henney",
      "orcid": "0000-0001-6208-9109"
    },
    {
      "affs": [
        2,
        5
      ],
      "name": "A Z Lugo-Aranda"
    },
    {
      "affs": [
        6
      ],
      "name": "A Singh"
    },
    {
      "affs": [
        7
      ],
      "name": "E J Johnston",
      "orcid": "0000-0002-2368-6469"
    },
    {
      "affs": [
        8
      ],
      "name": "A Roman-Lopes"
    },
    {
      "affs": [
        2
      ],
      "name": "C G Román-Zúñiga"
    },
    {
      "affs": [
        1
      ],
      "name": "I Cruz-Gonzalez"
    },
    {
      "affs": [
        9
      ],
      "name": "Guy S Stringfellow",
      "orcid": "0000-0003-1479-3059"
    },
    {
      "affs": [
        1
      ],
      "name": "M Peña"
    },
    {
      "affs": [
        2
      ],
      "name": "A Wofford",
      "orcid": "0000-0001-8289-3428"
    },
    {
      "affs": [
        10
      ],
      "name": "E Egorova"
    },
    {
      "affs": [
        2
      ],
      "name": "O Aranguré"
    },
    {
      "affs": [
        1
      ],
      "name": "L C Castañeda-Carlos"
    },
    {
      "affs": [
        1
      ],
      "name": "S Torres-Peimbert"
    },
    {
      "affs": [
        1,
        11
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      "name": "L Hernández-Martínez"
    },
    {
      "affs": [
        12
      ],
      "name": "J R Brownstein",
      "orcid": "0000-0002-8725-1069"
    },
    {
      "affs": [
        1
      ],
      "name": "R de J Zermeño"
    },
    {
      "affs": [
        13,
        14,
        15
      ],
      "name": "I Yu Katkov"
    },
    {
      "affs": [
        10
      ],
      "name": "Oleg V Egorov"
    },
    {
      "affs": [
        16
      ],
      "name": "A J Mejía-Narváez"
    },
    {
      "affs": [
        17,
        16
      ],
      "name": "G A Blanc"
    },
    {
      "affs": [
        2
      ],
      "name": "Mónica A Villa-Durango"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d5hn1zays293k.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag2118",
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    "0035-8711",
    "1365-2966"
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  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/d5hn1zays293k.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T00:21:01Z",
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "journal-openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
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  ],
  "title": "SDSS-V LVM: Revealing the Physical and Chemical Structure of the Helix Nebula",
  "title_text": "SDSS-V LVM: Revealing the Physical and Chemical Structure of the Helix Nebula",
  "type": "peer-reviewed",
  "updated_at": "2026-11-07T00:21:00Z",
  "url": "https://research.draconitic.com/paper/d5hn1zays293k",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}