{
  "abstract": "Anticyclonic vortices are promising sites for planetesimal formation in the dead zones of protoplanetary discs. The subcritical baroclinic instability (SBI) can amplify and sustain such vortices, but requires a seed perturbation of sufficient amplitude, a threshold that has so far only been probed empirically. We characterise the boundary separating the laminar Keplerian basin of attraction from the self-sustained vortical one by applying an edge-tracking (bisection) algorithm to the two-dimensional Boussinesq shearing sheet, over an extensive grid of Reynolds, Péclet, and Richardson numbers. At all explored parameters, the computed edge state is a streamwise-elongated anticyclone satisfying the Kida vorticity/aspect-ratio relation, associated with a thermal dipole tilted away from the background entropy gradient by a diffusion-controlled angle. We construct a predictive model of the edge state, in which a marginal enstrophy balance combining the Kida relation with shear-enhanced thermal relaxation yields closed-form power laws for the critical vorticity and radial width of the seed as functions of the flow parameters, in quantitative agreement with the numerical scalings. The edge-state framework thus provides a possible predictive criterion applicable to candidate vortical seeds in protoplanetary discs.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "name": "Florence Marcotte"
    },
    {
      "name": "Yannick Ponty"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bnw4n16hag0pe.bib",
  "cited_by": 0,
  "doi": null,
  "fulltext_url": null,
  "id": "bnw4n16hag0pe",
  "issns": [],
  "landing_url": "https://hal.science/hal-05751296v1",
  "language": "en",
  "licence": "CC-BY-NC-4.0",
  "licence_label": "CC BY-NC 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdu"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://hal.science/hal-05751296/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bnw4n16hag0pe.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:35Z",
      "native_id": "hal-05751296",
      "source": "hal",
      "url": "https://hal.science/hal-05751296v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "hal:0.sdu",
      "subfield": "general"
    }
  ],
  "title": "On the edge of subcritical baroclinic instability in a local model of accretion disc",
  "title_text": "On the edge of subcritical baroclinic instability in a local model of accretion disc",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:35Z",
  "url": "https://research.draconitic.com/paper/bnw4n16hag0pe",
  "venue": "HAL",
  "versions": []
}