![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 […]
K dwarf
![Plots of the observed, high signal-to-noise H (top panel) band IGRINS spectra used in this abundance analysis. Oxygen abundances are determined from OH lines located in the H band (1.45–1.80 microns) while carbon, 12C/ 13C, and 16O/ 18O abundances are derived from various CO isotopologue lines located in the 2.3-2.45 micron region of the K band (1.95–2.45 microns). -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/11/Expanding.png?resize=1200%2C721&ssl=1)
Posted inExoplanets, -moons, -comets
Expanding the Volatile Abundance Inventory for High-Priority K-Dwarf JWST Exoplanet Systems
[astro-ph.SR] There are exceedingly few chemical abundance measurements available in the literature for K dwarf stars, especially for those with Teff< 4700 K due to an incompatibility of traditional analyses […]
Posted inBiosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release
A New Census Of Our Sun’s Neighbors Reveals The Best Potential Real Estate For Life
A new study led by a Georgia State University astronomy graduate student is a major step forward in the search for stars that could host Earth-like planets that may prove […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Interstellar, Press Release
Lyman-Alpha Emission From K And M Dwarfs: Intrinsic Profiles, Variability, And Flux In The Habitable Zone
Lyman-α (Lyα) is the most prominent ultraviolet emission line in low-mass stars, playing a crucial role in exoplanet atmospheric photochemistry, heating, and escape.
Posted inAstrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
A Perfect Tidal Storm: HD 104067 Planetary Architecture Creating an Incandescent World
The discovery of planetary systems beyond the solar system has revealed a diversity of architectures, most of which differ significantly from our system.
Posted inExoplanets, -moons, -comets, Habitable Zones, Status Report
Surrounded By Giants: Habitable Zone Stability Within The HD 141399 System
The search for exoplanets has revealed a diversity of planetary system architectures, the vast majority of which diverge significantly from the template of the solar system.