{
  "abstract": "Stripped-envelope supernovae provide a window into how massive stars lose their layers, mix radioactive material, produce dust, and explode asymmetrically. We present optical, near-infrared (NIR), and mid-infrared (MIR) observations of SN~2025aico, a Type~IIb supernova in LEDA~35384. Our spectroscopic sequence, spanning $+1$ to $+167$ d after explosion, follows its evolution from a photospheric phase exhibiting both hydrogen and helium features to prominent helium emission and, ultimately, nebular-phase ejecta. Using He I $1.083$ and $2.0581\\,μ$m transitions, we investigated the kinematics and geometry of the helium-rich material. Both transitions exhibit a three-phase, non-monotonic velocity evolution: an initial rapid decline, a subsequent increase, and an eventual plateau. We interpret this behavior as evidence for limited outward mixing of $^{56}$Ni, such that radioactive energy deposition reaches the outer helium-rich ejecta progressively as the ejecta expand, producing the non-thermal electrons responsible for helium excitation. After $\\sim100$ d, both NIR He I transitions develop double-peaked emission profiles. Similar structure in the oxygen emission indicates ejecta asymmetry. Comparison with other supernovae suggests a tentative connection between this structure and explosion energy, potentially linked to the delay between core collapse and explosion. Serendipitous JWST observations at $+124.4$d reveal an infrared excess. Modeling favors warm ($\\sim800$--$1500$K) carbon dust newly formed in the ejecta, together with cooler carbon or silicate dust likely associated with pre-existing circumstellar material. SN~2025aico demonstrates how continuous optical-to-MIR observations can connect progenitor evolution, explosion physics, ejecta geometry, and dust production.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.26935",
  "author_total": 11,
  "authors": [
    {
      "name": "Grace Davis"
    },
    {
      "name": "Kyle Medler"
    },
    {
      "name": "Chris Ashall"
    },
    {
      "name": "Willem B. Hoogendam"
    },
    {
      "name": "Cameron Pfeffer"
    },
    {
      "name": "David O. Jones"
    },
    {
      "name": "Shunsaku Horiuchi"
    },
    {
      "name": "Tyco Mera"
    },
    {
      "name": "Benjamin Shappee"
    },
    {
      "name": "Charlotte Ward"
    },
    {
      "name": "Grace Showerman"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ffnrdknyg5711.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.26935",
  "fulltext_url": null,
  "id": "ffnrdknyg5711",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.26935",
  "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.HE"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ],
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7214209440",
  "pdf_url": "https://arxiv.org/pdf/2609.26935",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ffnrdknyg5711.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2609.26935",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.26935"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "SN2025aico: An Interesting Case Of $^{56}$Ni Mixing, Ejecta Asymmetries, and Dust Formation in a Type IIb Supernova",
  "title_text": "SN2025aico: An Interesting Case Of ^56Ni Mixing, Ejecta Asymmetries, and Dust Formation in a Type IIb Supernova",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/ffnrdknyg5711",
  "venue": "arXiv",
  "versions": []
}