{
  "abstract": "Asteroseismology relies on disk-integrated photometry or radial velocities, in which geometric cancellation suppresses modes of high spherical degree ($l\\geq4$). Observations are thus limited to deeply penetrating, low-degree modes, leaving the outer envelope inaccessible. We investigate whether a high-magnification microlensing event can temporarily lift this limitation by differentially magnifying the surface of an oscillating source star. We modelled the visibility of solar-like oscillations during microlensing, weighting the surface by limb darkening and the local magnification. We computed multiplet visibilities and the power distribution among azimuthal components, and built a likelihood model for recovering the 3D spin-axis orientation from resolved rotational multiplets. When the lens-source separation becomes comparable to the source's angular radius, the magnification gradient acts as a transient spatial filter that breaks the symmetry of disk integration, raising high-degree mode visibilities by up to three orders of magnitude. The same non-axisymmetric weighting makes the relative power of azimuthal components depend on both the inclination and sky-projected azimuth of the spin axis, imprinting the full spin orientation onto the power spectrum. With $5\\%$ relative-power uncertainties, we recover the orientation to $σ_i=2.9^\\circ$ and $σ_γ=11.5^\\circ$. Microlensing thus does more than amplify distant stars: its magnification pattern enables spatially selective asteroseismology. The effect is strongest for rare close encounters and unlikely to support large samples, and the newly visible high-degree modes will overlap with rotationally split and mixed modes, complicating mode identification. Nevertheless, individual high-quality events may open a window on envelope physics and spin geometries for stars in the Galactic bulge and beyond.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.28005",
  "author_total": 2,
  "authors": [
    {
      "name": "Marcus L. Marcussen"
    },
    {
      "name": "Mikkel N. Lund"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2144t5xrtygm2.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.28005",
  "fulltext_url": null,
  "id": "2144t5xrtygm2",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.28005",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ],
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "astro-ph.IM"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.28005",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2144t5xrtygm2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:04Z",
      "native_id": "2610.28005",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.28005"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Phakoseismology: Asteroseismology of gravitationally microlensed stars",
  "title_text": "Phakoseismology: Asteroseismology of gravitationally microlensed stars",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:04Z",
  "url": "https://research.draconitic.com/paper/2144t5xrtygm2",
  "venue": "arXiv",
  "versions": []
}