{
  "abstract": "Large spectroscopic surveys require robust pipelines capable of inferring stellar parameters over a wide range of the Hertzsprung–Russell (H-R) diagram from data of varying quality. SDSS-V is one such survey, where the data from the lower-resolution, optical BOSS spectrograph will provide a large dataset covering a wide range of Galactic stellar populations. To better analyze these data, we present BOSS-CLAM, a generative, forward-modeling pipeline for inferring effective temperature ( T eff ), surface gravity ( log g ), metallicity ([Fe/H]), and α -abundance ([ α /M]) from continuum-normalized BOSS spectra. BOSS-CLAM maps stellar labels to nonnegative matrix factorization (NMF) basis vector weights via a polynomial mapping jointly optimized with the spectral decomposition, which provides a more flexible framework for working with the lower-resolution BOSS data. Additionally, training labels are drawn from four complementary sources (ASPCAP, BOSS-MINESweeper , wide binaries, and a hot star validation sample), which enables coverage from cool M dwarfs through hot OB stars, and across a wide range of metallicity. We infer parameters for 1,708,214 BOSS spectra, with a recommended clean catalog of 915,514 sources. Validation against open and globular clusters demonstrates homogeneous, accurate abundances across a wide range of metallicity. Wide binary tests yield abundance uncertainties of σ [Fe/H] ≈ 0.15 dex and σ [ α /M] ≈ 0.06 dex at signal-to-noise ratio (SNR) = 10. Finally, we demonstrate that the BOSS-CLAM catalog recovers known chemical structure of the Milky Way disk and is well suited for Galactic archaeology, chemical tagging, and stellar population modeling. The pipeline, trained model, and catalog are publicly released as part of SDSS-V DR20.",
  "abstract_shown": true,
  "affiliations": [
    "Vanderbilt University",
    "University of Toronto",
    "Monash University",
    "Flatiron Institute",
    "University of Chicago",
    "NSF-Simons AI Institute for the Sky (SkAI)",
    "Texas Christian University",
    "Georgia State University",
    "Observatories of the Carnegie Institution for Science",
    "Johns Hopkins University",
    "Max Planck Institute for Astronomy",
    "University of Heidelberg",
    "Institute of Astronomy",
    "Center for Astrophysics ∣Harvard & Smithsonian",
    "The Observatories of the Carnegie Institution for Science",
    "New York University",
    "University of Colorado Boulder",
    "University of Illinois at Urbana-Champaign"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 16,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Ilija Medan",
      "orcid": "0000-0003-3410-5794"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Andrew R. Casey",
      "orcid": "0000-0003-0174-0564"
    },
    {
      "affs": [
        4,
        5
      ],
      "name": "Alexander P. Ji",
      "orcid": "0000-0002-4863-8842"
    },
    {
      "affs": [
        6
      ],
      "name": "Jonah M. Otto",
      "orcid": "0000-0003-2602-4302"
    },
    {
      "affs": [
        7
      ],
      "name": "Kayvon Sharifi",
      "orcid": "0009-0006-3626-7585"
    },
    {
      "affs": [
        7
      ],
      "name": "Zachary Way",
      "orcid": "0000-0003-0179-9662"
    },
    {
      "affs": [
        8
      ],
      "name": "Madeleine McKenzie",
      "orcid": "0000-0002-1715-1257"
    },
    {
      "affs": [
        9
      ],
      "name": "Natalie R. Myers",
      "orcid": "0000-0001-9738-4829"
    },
    {
      "affs": [
        0
      ],
      "name": "Keivan G. Stassun",
      "orcid": "0000-0002-3481-9052"
    },
    {
      "affs": [
        10,
        11
      ],
      "name": "Peter J. Smith",
      "orcid": "0000-0002-7489-5244"
    },
    {
      "affs": [
        12
      ],
      "name": "Andrew Tkachenko",
      "orcid": "0000-0003-0842-2374"
    },
    {
      "affs": [
        13
      ],
      "name": "Vedant Chandra",
      "orcid": "0000-0002-0572-8012"
    },
    {
      "affs": [
        14,
        15
      ],
      "name": "Michael R. Blanton",
      "orcid": "0000-0003-1641-6222"
    },
    {
      "affs": [
        6
      ],
      "name": "Peter M. Frinchaboy",
      "orcid": "0000-0002-0740-8346"
    },
    {
      "affs": [
        16
      ],
      "name": "Guy S. Stringfellow",
      "orcid": "0000-0003-1479-3059"
    },
    {
      "affs": [
        17
      ],
      "name": "Sean Morrison",
      "orcid": "0000-0002-6770-2627"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/18fwb3b2n42d3.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4365/aea56f",
  "fulltext_url": null,
  "id": "18fwb3b2n42d3",
  "issns": [
    "0067-0049",
    "1538-4365"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea56f",
  "language": null,
  "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": [
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
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  "openalex": "W7171569183",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea56f/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/18fwb3b2n42d3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:15Z",
      "native_id": "10.3847/1538-4365/aea56f",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea56f"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "BOSS-CLAM: Utilizing a Constrained Linear Absorption Model to Infer Stellar Parameters from BOSS Spectra",
  "title_text": "BOSS-CLAM: Utilizing a Constrained Linear Absorption Model to Infer Stellar Parameters from BOSS Spectra",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:15Z",
  "url": "https://research.draconitic.com/paper/18fwb3b2n42d3",
  "venue": "The Astrophysical Journal Supplement Series",
  "versions": []
}