![Modern Earth clear-atmosphere transmission spectrum at R ∼ 105 with molecule-by-molecule attribution over 0.4-1.8 µm. In all panels, species are color-coded as in the legend. (A) Continuum-subtracted transit-depth excess (Rp/Rs) 2 (black), measured relative to the 5th-percentile continuum floor (gray fill), with muted “only-molecule” traces of the active absorbers. (B) Molecular contributions ∆ = (full − leave-one-out) in ppm for the same wavelength; O2 and H2O dominate selected optical-NIR intervals, while CO2, CH4, CO, HCN, C2H6, and O3 provide weaker secondary features. (C) Offset contribution zooms over 0.68-1.30 µm isolating the O2 B/A and 1.27 µm bands (upper) against overlapping H2O (lower). (D) Offset contribution zooms over 1.35-1.75 µm through the near-infrared H2O/CO2/CH4 forest (top to bottom). O3 contributions appear only where the O3 line list is available (λ ≳ 1.4 µm). Aerosols are not considered in the radiative transfer.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/11/From-Anoxic.png?resize=1200%2C717&ssl=1)
[astro-ph.EP]. 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 […]
ELT/ANDES
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Probing The Atmospheres Of Young Long-Period Sub-Neptune Progenitors With ELT/ANDES
High-resolution cross-correlation spectroscopy (HRCCS) has emerged as a powerful technique for detecting and characterizing exoplanet atmospheres from the ground.