{
  "abstract": "Constraining atmospheric loss is crucial for understanding the evolution of planetary atmospheres. We report the detection of an evaporating exosphere from TOI-3884b, a super-Neptune in a polar orbit around an M4 dwarf star. We infer this evaporation from a 6.8$\\pm$0.27\\% excess transit depth in the He I 10830 Å\\, line, observed during five transits of TOI-3884b with the Habitable Zone Planet Finder spectrometer. While we observe outflow signatures starting as early as 5 hours before the onset of the planet's optical transit, no significant post-transit tail is detected. Hitherto, such a pre-transit headwind without a significant post-transit tail has only been detected from HAT-P-67b, a hot Saturn orbiting an F-type star. This asymmetric outflow morphology supports irradiation-driven mass loss over core-heated mass loss, and we explore whether this could be caused by sub-Alfvén star-planet interaction. The detection of such complex outflow morphologies is now opening a new window, enabling us to test theories of star-planet interactions and planetary magnetic fields with observations.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.31492",
  "author_total": 22,
  "authors": [
    {
      "name": "Joe P. Ninan"
    },
    {
      "name": "Jessica Libby-Roberts"
    },
    {
      "name": "Suvrath Mahadevan"
    },
    {
      "name": "Oleg Kochukhov"
    },
    {
      "name": "Daniel M. Krolikowski"
    },
    {
      "name": "Gudmundur Stefansson"
    },
    {
      "name": "Shubham Kanodia"
    },
    {
      "name": "Jaume Orell-Miquel"
    },
    {
      "name": "Caroline V. Morley"
    },
    {
      "name": "Kevin France"
    },
    {
      "name": "Girish Duvvuri"
    },
    {
      "name": "Chad F. Bender"
    },
    {
      "name": "William D. Cochran"
    },
    {
      "name": "Megan Delamer"
    },
    {
      "name": "Scott A. Diddams"
    },
    {
      "name": "Samuel Halverson"
    },
    {
      "name": "Fred Hearty"
    },
    {
      "name": "Leslie Hebb"
    },
    {
      "name": "Andrew Monson"
    },
    {
      "name": "Paul Robertson"
    },
    {
      "name": "Arpita Roy"
    },
    {
      "name": "Christian Schwab"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c9vhwhtsy4sp7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.31492",
  "fulltext_url": null,
  "id": "c9vhwhtsy4sp7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.31492",
  "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"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7223387478",
  "pdf_url": "https://arxiv.org/pdf/2610.31492",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c9vhwhtsy4sp7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:34Z",
      "native_id": "2610.31492",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.31492"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "A Headwind-like Helium Outflow from TOI-3884b",
  "title_text": "A Headwind-like Helium Outflow from TOI-3884b",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:34Z",
  "url": "https://research.draconitic.com/paper/c9vhwhtsy4sp7",
  "venue": "arXiv",
  "versions": []
}