![Surviving CH4 fraction as a function of depth below the surface and effective GCR exposure time. The colour scale gives the CH4 abundance relative to its initial value, while the dashed contours indicate 90%, 50%, and 10% remaining CH4. Vertical dashed lines mark the 3σ viable GCR exposure range of 0.87 - 3.12 Gyr. Increasing GCR exposure progressively extends CH4 depletion to greater depths while more deeply shielded layers retain a larger fraction of their primordial CH4. --[astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Delayed.png?resize=1200%2C713&ssl=1)
[astro-ph.EP] Interstellar comet 3I/ATLAS shows unusual volatile activity, including strong H2O, CO, and CO2 production and a delayed post-perihelion detection of CH4.
astro-ph.EP
![Radial gas temperature maps for planets within the in-house 3D GCM framework. The panels illustrate equatorial slice plots of (Tgas, pgas) across three global temperature regimes: 800 K (left), 1600 K (center), and 2400 K (right). Host star types vary by row, descending from A-type to G-type and M-type stars [1] -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Faithful.png?resize=1200%2C717&ssl=1)
Posted inExoplanets, -moons, -comets
Faithful Neural Embeddings For 3D Exoplanet Climate Modeling
[astro-ph.EP] With the rapid advancement of telescopes like JWST and Ariel, there is an urgent need for efficient 3D climate models to interpret observations of exoplanet atmospheres.
Posted inEuropa
Europa Smooth Plains Formation: A SPH Cryovolcanic Model
[astro-ph.EP] Cryovolcanism is a fundamental geodynamical process that has been observed on several icy moons. Europa stands out as a primary target for investigating potential cryovolcanic activity and its role […]
![Orbit of 3I/ATLAS showing the 17 UVES/VLT observing epochs. Open and filled circles represent pre- and post-perihelion observations, respectively. Planet positions with filled circles are shown for the date of perihelion. The open diamond marks Earth’s position at the discovery of 3I/ATLAS, while the open circles along Earth’s orbit indicate its position at each observing epoch. [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/High-resolution.png?resize=1200%2C720&ssl=1)
Posted inComets and Asteroids
High-resolution Optical Spectroscopy Reveals The Distinctive Volatile Composition Of The Interstellar Comet 3I/ATLAS
[astro-ph.EP] Comets preserve volatile material from the early stages of planetary-system formation. The discovery of the interstellar comet 3I/ATLAS enables a direct comparison between a comet formed around another star […]
Posted inImaging & Spectroscopy
The Science Potential of Characterizing Gas Giant Exoplanets with HWO
[astro-ph.EP] With the ability to directly image Earth-like exoplanets and search their atmospheres for biosignatures, the upcoming Habitable Worlds Observatory (HWO) will also collect high signal-to-noise ratio (S/N) reflected-light photometry […]
Posted inAtmospheres, Climate, Weather
Optical Constants of Photochemical Haze Analogs in N2-CH4-CO Atmospheres from 0.4 to 28.6 μm
[astro-ph.EP] Photochemical hazes play an important role in shaping the spectra and radiative balance of N2-dominated planetary atmospheres.
![Top-down, to-scale view of the TOI-789 architecture. The four planetary orbits are drawn around the M3 host (center); symbol size scales with planetary radius and symbol color with equilibrium temperature (color bar). The candidate .04 is drawn with a dashed outline. Shaded annular bands mark, from the inside out, the Venus zone (Kane et al. 2014), the temperate region defined by Teq = 273– 400 K, and the inner edge of the Kopparapu et al. (2014) habitable zone. The four planets form a sequence of decreasing insolation that crosses the Venus zone, with the candidate .04 near the inner edge of the habitable zone.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Characterization.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
Characterization of the Compact Multi-planet System TOI-789: Validation of Three Terrestrial Planets, Dynamical Characterization, and Detection of a Fourth Temperate Candidate
[astro-ph.EP] We present the validation and dynamical characterization of TOI-789 (TIC 300710077), a compact multi-planet system around an M3 dwarf at 43 pc.
Posted inAstrochemistry
JWST Reveals Refractory-Rich Water Ice in Interstellar Comet 3I/ATLAS: Evidence for a Continuum of Grain Properties across Protoplanetary Disks
[astro-ph.EP] We present JWST/NIRSpec PRISM observations of the interstellar comet 3I/ATLAS obtained on 2025 August 6 (Epoch 1), 2025 December 22 (Epoch 2), and 2026 April 1 (Epoch 3), spanning […]
![Top view schematic of the experimental geometry at the PWK1 plasma wind tunnel facility. The geometrical thickness 𝑠 denotes the extent of the radiating plasma along the line of sight as observed by the Echelle spectrometer. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Determining.png?resize=1200%2C718&ssl=1)
Posted inMeteorites & Asteroids
Determining Elemental Composition In Laboratory Meteorite Ablation Spectra Through Radiative Transfer Modeling
[astro-ph.EP] Laboratory simulations of meteor ablation provide a critical quantitative link between the chemical composition of meteoroids and their observed spectral features.
Posted inComets and Asteroids
Fragmentation Dynamics of Pristine Interstellar Comets: An Exploratory Multi-Physics Simulation Study
[astro-ph.EP] We present an exploratory numerical model for the thermal evolution and fragmentation of pristine interstellar comets during a first passage through the inner Solar System, and we apply it […]