{
  "abstract": "Earth's atmosphere evolved from an anoxic, methane-bearing Archean state through Proterozoic oxygenation to the O$_2$-rich modern atmosphere. However, most biosignature detectability studies focus on modern Earth, leaving earlier atmospheric states comparatively unexplored. We investigate how atmospheric evolution and stellar environments influence the detectability of O$_2$, CH$_4$, H$_2$O, and CO$_2$, and their potential to distinguish anoxic from oxygenated atmospheres. We construct two complementary photochemical grids: representative Archean, Proterozoic, and modern-Earth scenarios around the Sun, and four geological epochs (3.9, 2.0, 0.8 Ga, and modern Earth) across FGKM hosts. Combining one-dimensional photochemical modeling, high-resolution transmission spectral simulations, and instrument-noise modeling, we assess molecular detectability with ELT/ANDES under optimistic photon-noise-limited conditions. For solar-host Archean and Proterozoic models, CH$_4$ requires approximately 33 and 42 transits, respectively, to reach the adopted 5$σ$ criterion, whereas O$_2$ remains below 3$σ$ within the observing limits. Modern-Earth O$_2$ reaches 3$σ$ after approximately 38 transits. Across the FGKM grid, O$_2$ does not reach 5$σ$ for the 3.9 Ga models. However, For the M3V, K2V, and M8V proxies, modern-Earth O$_2$ reaches 5$σ$ in 9, 15, and 20 transits, respectively, whereas CH$_4$ requires 11, 12, and 28 transits at 3.9 Ga and only 2--4 transits across the oxygenated epochs. These results reveal a strong O$_2$ detectability contrast around M and K-dwarfs, but not Sun-like hosts in the YJH bands. Robust biosignature interpretation requires complementary molecular constraints, including informative non-detections, within the context of atmospheric evolution and stellar environment.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.41621",
  "author_total": 3,
  "authors": [
    {
      "name": "Dwaipayan Dubey"
    },
    {
      "name": "Spandan Dash"
    },
    {
      "name": "Liton Majumdar"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5dm1z4trsqgdw.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.41621",
  "fulltext_url": null,
  "id": "5dm1z4trsqgdw",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.41621",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.41621",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5dm1z4trsqgdw.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T12:21:15Z",
      "native_id": "2610.41621",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.41621"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures across Stellar Hosts with ELT/ANDES",
  "title_text": "From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures across Stellar Hosts with ELT/ANDES",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:51Z",
  "url": "https://research.draconitic.com/paper/5dm1z4trsqgdw",
  "venue": "arXiv",
  "versions": []
}