From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures across Stellar Hosts with ELT/ANDES
Abstract
Earth's atmosphere evolved from an anoxic, methane-bearing Archean state through Proterozoic oxygenation to the O2-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 O2, CH4, H2O, and CO2, 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, CH4 requires approximately 33 and 42 transits, respectively, to reach the adopted 5σ criterion, whereas O2 remains below 3σ within the observing limits. Modern-Earth O2 reaches 3σ after approximately 38 transits. Across the FGKM grid, O2 does not reach 5σ for the 3.9 Ga models. However, For the M3V, K2V, and M8V proxies, modern-Earth O2 reaches 5σ in 9, 15, and 20 transits, respectively, whereas CH4 requires 11, 12, and 28 transits at 3.9 Ga and only 2--4 transits across the oxygenated epochs. These results reveal a strong O2 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.
Related
- The role of source geometry and atmospheric propagation in global bolide infrasound detectability
- Size, atmospheric, and ring constraints on the large Kuiper belt object (55565) Aya from a stellar occultation
- The impact of M dwarf stellar convection on exoplanetary atmospheric signatures. A 3D radiation-hydrodynamics simulation analysis for high-resolution spectroscopy
- A JWST Transiting Survey of FGK Stellar Limb Darkening: Empirical Evidence for Quadratic Laws and Atmospheric Model Comparisons
- A JWST transiting survey of FGK stellar limb darkening: empirical evidence for quadratic laws and atmospheric model comparisons
BibTeX
@misc{dubey2026from,
title = {{From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures across Stellar Hosts with ELT/ANDES}},
author = {Dwaipayan Dubey and Spandan Dash and Liton Majumdar},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.41621},
eprint = {2610.41621},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.41621},
note = {CC0},
}
RIS
TY - UNPB
TI - From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures across Stellar Hosts with ELT/ANDES
AU - Dwaipayan Dubey
AU - Spandan Dash
AU - Liton Majumdar
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.41621
UR - https://arxiv.org/abs/2610.41621
AB - 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_2O, 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 5σ criterion, whereas O_2 remains below 3σ within the observing limits. Modern-Earth O_2 reaches 3σ after approximately 38 transits. Across the FGKM grid, O_2 does not reach 5σ for the 3.9 Ga models. However, For the M3V, K2V, and M8V proxies, modern-Earth O_2 reaches 5σ 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.
ER -