{
  "abstract": "We present a comprehensive analysis of the long-term photometric and spectroscopic monitoring campaign of the Type IIn Supernova (SN) 2024kgi. The SN reaches at peak an $r$-band absolute magnitude of $-19.81 \\pm 0.06$ mag and a bolometric luminosity of $\\sim 2 \\times 10^{43}$ erg s$^{-1}$. We observe a break in the lightcurve at day $\\sim 312$, after which the luminosity decline changes from $t^{-1.0}$ to $t^{-4.5}$, likely due to the shock sweeping the dense CSM. We introduce a semi-analytical lightcurve modeling approach for CSM-interaction in transients that accounts for variable diffusion time. We hence estimate a CSM mass of $2.34^{+11.8}_{-1.6} M_{\\odot}$ and with a density profile $ρ_{csm} \\propto r^{-2.74}$, indicating progressively increasing mass loss toward the SN explosion. The ejecta signatures emerge as broad H, He, and Ca II triplet lines, at day $\\sim 80$, much earlier than expected from a spherically symmetric CSM, suggesting asymmetry in the CSM. After the lightcurve break, the H lines exhibit a wavelength-dependent deficit in the red-wing flux, indicating new dust formation in the ejecta and/or in the post-shock gas. We observe an NIR excess from day $\\sim 40$ onwards. We attribute the early NIR excess before the lightcurve break solely to the NIR echo from pre-existing dust, as there are no other indications for new dust formation. The late-time NIR excess likely has contributions from both the preexisting and newly formed dust. The steady increase in mass loss, slow CSM velocity, and asymmetric CSM favor a binary interaction-induced mass loss.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.25233",
  "author_total": 33,
  "authors": [
    {
      "name": "Naveen Dukiya"
    },
    {
      "name": "Kuntal Misra"
    },
    {
      "name": "Andrea Pastorello"
    },
    {
      "name": "Andrea Reguitti"
    },
    {
      "name": "Anjasha Gangopadhyay"
    },
    {
      "name": "Aravind P. Ravi"
    },
    {
      "name": "Brian Hsu"
    },
    {
      "name": "Noah Franz"
    },
    {
      "name": "David J. Sand"
    },
    {
      "name": "Nathan Smith"
    },
    {
      "name": "Jennifer E. Andrews"
    },
    {
      "name": "Moira Andrews"
    },
    {
      "name": "K. Azalee Bostroem"
    },
    {
      "name": "Collin Christy"
    },
    {
      "name": "Monalisa Dubey"
    },
    {
      "name": "Joseph R. Farah"
    },
    {
      "name": "Archana Gupta"
    },
    {
      "name": "Estefania Padilla Gonzalez"
    },
    {
      "name": "Emily Hoang"
    },
    {
      "name": "D. Andrew Howell"
    },
    {
      "name": "Curtis McCully"
    },
    {
      "name": "Darshana Mehta"
    },
    {
      "name": "Megan Newsome"
    },
    {
      "name": "Jeniveve Pearson"
    },
    {
      "name": "Nicolas Meza Retamal"
    },
    {
      "name": "Jeonghee Rho"
    },
    {
      "name": "Manisha Shrestha"
    },
    {
      "name": "Bhagya Subrayan"
    },
    {
      "name": "Giacomo Terreran"
    },
    {
      "name": "Lina Tomasella"
    },
    {
      "name": "Stefano Valenti"
    },
    {
      "name": "Giorgio Valerin"
    },
    {
      "name": "Kathryn Wynn"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3qk805e76crfa.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.25233",
  "fulltext_url": null,
  "id": "3qk805e76crfa",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.25233",
  "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": "W7214101061",
  "pdf_url": "https://arxiv.org/pdf/2609.25233",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3qk805e76crfa.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:39Z",
      "native_id": "2609.25233",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.25233"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Early NIR echo and the time variable mass loss history of Type IIn SN 2024kgi",
  "title_text": "Early NIR echo and the time variable mass loss history of Type IIn SN 2024kgi",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:39Z",
  "url": "https://research.draconitic.com/paper/3qk805e76crfa",
  "venue": "arXiv",
  "versions": []
}