![Vertical profiles of temperature and volume mixing ratios for the species included in our atmospheric model, simulated for TRAPPIST-1 e. The profile behavior follows from the equations and assumptions described in Section 2.2. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Biosignature-Detectability.png?resize=1200%2C720&ssl=1)
[astro-ph.EP] The search for life beyond the Solar System is at a turning point, transitioning from theoretical predictions to observations enabled by next-generation observatories.
atmosphere
Posted inExoplanets, -moons, -comets
Distant Exoplanets May Be Hiding Water Beyond Webb Telescope’s Reach, Study Finds
[University of Chicago] The planets that appear most common in the universe could have a lot of water—but it could be hiding where telescopes can’t detect it, according to a […]
Posted inSETI & Technosignatures
Decolonizing Technosignatures: Reimagining Technosignatures Through An Indigenist Lens
[astro-ph.IM] There exist numerous proposals for potential technosignatures that we can search for, but they all tend to be deviations from possible naturally occurring signals. That is, technosignatures tend to […]
![Cartoon illustrating the effect of the runaway greenhouse transition on atmospheric composition for two rocky planets with identical He, H2O and CO2 inventories. With a thin He atmosphere, planets below the runaway greenhouse limit (right) will have He-rich upper atmospheres and may support surface liquid water. For planets inside the inner edge of the habitable zone (left), H2O from liquid water oceans and CO2 from carbonates are transported into the atmosphere, dramatically decreasing the scale height and making the transit spectrum of the planet flatter. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Climates-of-temperate.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
Climates Of Temperate Rocky Planets With He-dominated Atmospheres
[astro-ph.EP] We present radiative-convective modeling of rocky exoplanets with He-dominated atmospheres and low envelope mass fractions. Helium has a steeper adiabatic temperature profile than N2 and H2 as it has […]
![Schematic showing the thermal and atmospheric escape evolution of two interpretations of sub-Neptune interiors. In a standard planetary model, a silicate interior is distinct from a hydrogen-rich envelope. As the planet contracts, hydrogen is removed from the upper atmosphere via stellar heating, and the interior-envelope boundary does not significantly contract with time. The temperature at this interface can reach of order ∼ 10, 000 K at early ages. In the miscible model, the interior-envelope boundary is defined by a binodal surface, which delineates regions in which hydrogen and silicate are miscible or immiscible. The temperature at the binodal surface does not change significantly with time. The radial position of the binodal surface contracts with time, exsolving hydrogen into the base of the envelope, while hydrogen is also removed from the top of the upper atmosphere.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Testing-the.png?resize=1200%2C716&ssl=1)
Posted inExoplanets, -moons, -comets
Testing The Prevalence Of Hydrogen-silicate Miscibility In Young Sub-Neptunes
[astro-ph.EP] Hydrogen-silicate miscibility can significantly alter the interior structure and thermal evolution of sub-Neptunes. We consider the interplay between this miscibility and stellar-driven atmospheric escape.
![Geometry of the LTT 3780 planetary system at the time of our radio technosignature observations. The left panel shows the sky-plane (X–Y) view as seen from Earth, while the right panel shows the top-down (X–Z) view of the system. The orbits of planets b (blue) and c (green) are shown relative to the host star (yellow). Our observations from the ATA, mentioned in Table 1 on 5th November 2025, were timed to coincide with a planet–planet occultation (PPO), when planet b passes behind planet c along the line of sight, providing a unique configuration to search for radio technosignatures during mutual planetary alignment.-- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/A-Search-For.png?resize=1200%2C719&ssl=1)
Posted inSETI & Technosignatures
A Search For Narrowband Technosignatures From LTT 3780 With The Allen Telescope Array And The Karl G. Jansky Very Large Array
[astro-ph.IM] The LTT3780 system hosts two known exoplanets-LTT3780b, a rocky super-Earth, and LTT3780c, a temperate sub-Neptune-orbiting a nearby M dwarf on opposite sides of the radius valley. LTT3780c has been […]
Posted inExoplanets, -moons, -comets
First Completed Rocky Worlds Program Observations Open New Era in Exoplanet Studies
[STScI] Scientists leading the astronomy community’s most ambitious effort to study rocky planets outside of our solar system have reached a major milestone.
Posted inExoplanets, -moons, -comets
Nautilus Space Observatory: Unveiling the Diversity and Origin of Sub-Neptunes
[astro-ph.IM] Sub-Neptunes are the most common class of planets in the Galaxy, yet they have no Solar System analog and remain poorly understood as a population. JWST observations have revealed […]
Posted inBiosignatures & Paleobiology
White Paper On Phototrophic Biosignatures: Research Priorities For The Search For Life On Other Worlds
[astro-ph.IM] Photosynthesis is of prime interest in the telescopic search for life beyond the Solar System, because, on Earth, oxygenic photosynthesis produces two strong “biosignatures,” global scale signs of life […]
Posted inExoplanets, -moons, -comets
The Mid-Infrared Transmission Spectrum of the Temperate Sub-Neptune TOI-270 d
[astro-ph.EP] Observations of temperate sub-Neptunes with JWST have ushered in a new era for atmospheric characterization of small exoplanets.