![Radiogenic dose and the benefit of drilling. (a) GCR dose versus depth for constant-depth and steadily exhuming horizons, compared with the depth-independent radiogenic dose. Shading spans the radiogenic dose of the baseline composition at 3 Ga (0.9 MGy) and that of the regional GRS abundances at 3.9 Ga (5.6 MGy). Where a curve crosses the radiogenic level, the two doses are equal. (b) Total-dose reduction at 100–101 and 199–200 cm versus exposure age; dashed lines are the GCR-only shielding factors. Dotted lines mark effective ages for 10 and 100 nm yr−1 exhumation. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Radiation.png?resize=1200%2C720&ssl=1)
[astro-ph.EP] Amino acid enantiomeric excess (EE) is a potential biosignature, but its measurement requires sufficient surviving material as well as preserved chirality.
astro-ph.EP
![[LEFT] Extended Seasonal evolution of total atmospheric optical depth across 669 Sol (a) Total atmospheric optical depth for the control simulation (b) Total atmospheric optical depth under singleinjection aluminium nanoparticle substitution (c) Total optical-depth anomaly between the seeded and control simulations, showing the temporal evolution of the radiative effect associated with the aerosol substitution Extended [RIGHT]] Seasonal evolution of aerosol optical depth across 669 Sol (a) Aerosol optical depth for the control simulation, showing the spatial and temporal distribution of the background aerosol (b) Aerosol optical depth under single-injection aluminium nanoparticle substitution (c) Aerosol optical-depth anomaly between the seeded and control simulations, showing the evolution and decay of the aerosol optical signal in the absence of continuous replenishment. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/3D-Global.png?resize=1200%2C714&ssl=1)
Posted inTerraforming & Geoengineering
3D Global Climate Simulations of Synthetic Mars Warming
[astro-ph.EP] Artificial warming via engineered aerosols presents a novel pathway to bypass volatile scarcity on modern Mars.
Posted inAtmospheres, Climate, Weather
Simulations Of The Evolving Ozone Layer: Implications For The Early Earth, Exoplanets, And The Search For Life
[astro-ph.EP] Over 4 billion years, Earth’s atmosphere has been transformed from a composition devoid of molecular oxygen (O2) to one where O2 is now 21% of our modern atmosphere by […]
![Pressures determined by ruby fluorescence measurements at different locations within the sample chamber: (a) during powder compaction, (b) after decompression. No ruby fluorescence spectrum was obtained on the sphere marked with an asterisk, likely due to insufficient Cr doping, resulting in an undetectable fluorescence signal. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Elastic.png?resize=1200%2C720&ssl=1)
Posted inTitan
Elastic Properties of Titan Tholins Revealed by Brillouin Spectroscopy
[astro-ph.EP] Titan tholins, complex organic solids synthesized by simulating photochemical processes in Titan’s atmosphere, are widely regarded as analogs to organic surface materials on the Saturnian moon.
Posted inExoplanets, -moons, -comets
Ultraviolet Reflected-Light Spectroscopy of Modern Earth Analogs with Starshade Observations
[astro-ph.EP] Characterizing rocky, habitable zone planets in reflected light is a key science objective for future direct imaging missions, and the ultraviolet (UV) is uniquely suited for supporting the characterization […]
![Latitude-longitude maps of mean water vapour and hydrogen chloride volume mixing ratios and coefficient of variation (standard deviation divided by the mean) in percentage form at 20.91 km altitude. The values are calculated over four Venus solar days (468 Earth days). --[astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/How-long.png?resize=1200%2C717&ssl=1)
Posted inVenus
How Long Could Volcanic Plumes Persist In The Venus Atmosphere?
[astro-ph.EP] Resolving the ambiguity surrounding current Venusian volcanism is a primary objective for upcoming missions like EnVision and VERITAS.
![Set Transformer actor–critic architecture used by the RL policy. The input candidate set 𝑋 ∈ R 𝑁×𝐹 is first projected into a latent 𝑑-dimensional representation and processed by 𝐿 Induced Set Attention Blocks (ISABs). Learned inducing tokens provide the queries in the first attention operation of each ISAB, after which information is redistributed to the candidate tokens. The actor combines each contextualised target representation with the global mission state to produce one logit per available observation. Each logit is then converted into a probability to select a corresponding observation. The critic uses Pooling by Multihead Attention (PMA) to obtain a permutation-invariant summary of the candidate set, which is combined with the same global state to estimate 𝑉 (𝑠). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/aRieL-Reinforcement.png?resize=1200%2C715&ssl=1)
Posted inAriel Mission
aRieL – Reinforcement Learning For The Ariel Space Telescope Scheduling
[astro-ph.EP] The Ariel mission will conduct a population level survey of hundreds of exoplanet atmospheres, requiring observations to be scheduled across a large and diverse catalogue of potential targets.
Posted inExoplanets, -moons, -comets
The Accretionally Heated Atmospheres Of Protoplanets And Brown Dwarfs
[astro-ph.EP] The ranks of accreting planets and brown dwarfs are growing. To help interpret their spectra, we study how accretion affects a planet’s atmosphere. The atmosphere is irradiated from above […]
![Activity-age relationship for solar-type stars from Pezzotti et al. (2026). HD 219134 is denoted by the green square. Kepler LEGACY data from Pezzotti et al. (2026) are shown as cyan dots, Booth et al. (2017) data are indicated by salmon pentagons, and the Sun is shown by a black circled dot. The black lines indicate the linear fit from Booth et al. (2017) (dashed line) and Pezzotti et al. (2026) (dotted line). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detailed.png?resize=1200%2C718&ssl=1)
Posted inStellar Cartography
Detailed Study of HD 219134: A Benchmark K-dwarf With A Compact Planetary System
[astro-ph.EP] Space missions such as CoRoT, Kepler, and TESS have transformed asteroseismology and its synergies with exoplanet science.
![Temperature space-time diagram for the 300 K initial condition for the fiducial Earth model planet at (a) 0.930 AU (temperate state), and (b) 0.920 AU (post-runaway). The red contour denotes the 323 K isotherm.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Gen-EBM.png?resize=1200%2C697&ssl=1)
Posted inAtmospheres, Climate, Weather
Gen-EBM: An Energy Balance Model For Terrestrial Planets. Climate Multistability From Snowball To Post-runaway Greenhouse Climates
[astro-ph.EP] Climate multistability and tipping points are fundamental properties of planetary climates that depend sensitively on climate feedbacks.