{
  "abstract": "HD~158485 is an A-type $δ$~Scuti star in the CALSPEC network and the JWST absolute-flux calibration program. Gaia DR3 assigns it a binary classification probability close to unity but provides no orbital solution. Using TESS observations from Sectors 14--26, 40--41, 47--60, and 73--86, we measure the pulsation phases of six $δ$~Scuti modes. The frequencies form two groups with opposite light-travel-time delays, revealing two pulsating components. A direct light-curve forward model yields an orbital period of $P_{\\rm orb}=382.80^{+0.80}_{-0.76}$~d, eccentricity $e=0.242^{+0.045}_{-0.046}$, projected light-time amplitudes of $195.8^{+9.2}_{-8.9}$ and $239.7^{+6.8}_{-6.8}$~s, and a dynamical mass ratio of $q=M_B/M_A=0.818^{+0.046}_{-0.045}$. A blind prediction based only on the first two long TESS campaigns reproduces the third campaign without updating the orbital parameters, with a Pearson correlation coefficient of $r=0.983$. Its held-out rms is 83.8~s, compared with 289.9~s when the period is fixed at 365.25~d. A 5.15-$σ$ Hipparcos--Gaia EDR3 proper-motion anomaly independently indicates unresolved astrometric motion. The unresolved companion can also affect spectrophotometric predictions: a conditional PB2-constrained two-atmosphere model differs from the corresponding single-star atmosphere prediction by 1.6\\% over 1--5~$μ$m and 2.5\\% over 5--28~$μ$m. HD~158485 therefore shows that a calibration-relevant binary can lack a catalogued orbital solution while two independent pulsation clocks reveal and measure its orbit.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: 2026, ApJL, 1011, L20",
  "arxiv": "2610.14371",
  "author_total": 8,
  "authors": [
    {
      "name": "Chenglong Lv"
    },
    {
      "name": "Ali Esamdin"
    },
    {
      "name": "Shuguo Ma"
    },
    {
      "name": "Shahidin Yaqup"
    },
    {
      "name": "Haozhi Wang"
    },
    {
      "name": "Ayzada Jmahali"
    },
    {
      "name": "Jianwei Yao"
    },
    {
      "name": "Kedieryemu Kamili"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/259hsv3gmehdd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.14371",
  "fulltext_url": null,
  "id": "259hsv3gmehdd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.14371",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.14371",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/259hsv3gmehdd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:22Z",
      "native_id": "2610.14371",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.14371"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "TESS Pulsation Timing Reveals the JWST Calibration Star HD 158485 as a Double-pulsator Binary",
  "title_text": "TESS Pulsation Timing Reveals the JWST Calibration Star HD 158485 as a Double-pulsator Binary",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/259hsv3gmehdd",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/2041-8213/aeb301",
      "pid": "7gfs5w2pca2fk",
      "relation": "published-as",
      "title": "TESS Pulsation Timing Reveals the JWST Calibration Star HD 158485 as a Double-pulsator Binary",
      "venue": "The Astrophysical Journal Letters"
    }
  ]
}