{
  "abstract": "Nova 2021 Cassiopeia (V1405 Cas) was an ordinary J(175) neon nova with the white dwarf mass estimated to be M WD = 0.60 ± 0.10 M ⊙ . I found an orbital period of P = 0.1884 day and have tracked 20 times of photometric minima from 2013–2025. I measure that P increased from before to after the eruption with P pre = 0.1883919 ± 0.0000018 day and P post = 0.1884043 ± 0.0000018 day, for Δ P / P = 66 − 18 + 21 ppm. With correction for the angular momentum loss by the binary during the eruption, I derive that the nova ejected M ejecta = 7.5 × 10 ⁻⁴ M ⊙ , with an extreme range of (2.9–40) × 10 ⁻⁴ M ⊙ . The mass accreted during the previous eruption cycle comes from the trigger mass and is M accreted = (1.6 ± 0.4) × 10 ⁻⁴ M ⊙ . V1405 Cas provides counterexamples against five claims about cataclysmic variable (CV) evolution that have dominated since the 1980s. First, V1405 Cas has positive P ̇ , and this is contrary to the magnetic braking model. Second, the Δ P is 20× too small to allow the system to fade into a hibernation state. Third, M WD is decreasing over time, as shown by M ejecta > M accreted and by being a neon nova. Fourth, V1405 Cas is not a Type Ia supernova progenitor, for the same reasons. Fifth, the orbital period of V1405 Cas increased by +75 ppm from 2013–2025, as a counterexample to the pervasive idea that CVs are universally declining in period from evolution. V1405 Cas is the latest of recent measures of Δ P and P ̇ for 52 CVs and 25 X-ray binaries that have together refuted all five claims.",
  "abstract_shown": true,
  "affiliations": [
    "Louisiana State University"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Bradley E. Schaefer",
      "orcid": "0000-0002-2659-8763"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8cdabcs3w0bgx.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4357/aea146",
  "fulltext_url": null,
  "id": "8cdabcs3w0bgx",
  "issns": [
    "0004-637X",
    "1538-4357"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea146",
  "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"
    ]
  ],
  "openalex": "W7223177336",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea146/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/8cdabcs3w0bgx.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.3847/1538-4357/aea146",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea146"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "Classical Nova V1405 Cas Had M ejecta > M accreted and So Is Unlikely to Be a Type Ia Supernova Progenitor",
  "title_text": "Classical Nova V1405 Cas Had M ejecta > M accreted and So Is Unlikely to Be a Type Ia Supernova Progenitor",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/8cdabcs3w0bgx",
  "venue": "The Astrophysical Journal",
  "versions": []
}