![Simulated climates and observables for CO2-rich planets near the outer edge of the habitable zone. The illustration on the right depicts a potentially habitable world orbiting a Sun-like star. The teal point in the lower left section of the panel marks the orbital location of such a planet within the OHZ, and the corresponding reflected light spectrum that could be observed via direct imaging is shown in teal in the middle, left section of the panel. The upper left section of the panel shows an illustration of the same planet in a globally frozen state located just beyond the habitable zone. Its orbital position (lower left) and reflected light spectrum (middle) are shown in white. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/High-CO2.png?resize=1200%2C721&ssl=1)
[astro-ph.EP] The habitable zone (HZ) is a fundamental concept used to guide our search for temperate exoplanets with stable surface liquid water that would sustain remotely detectable biosignatures.
Biogeochemical Cycles & Geobiology
![Transmission spectra of TRAPPIST-1 c from the four JWST/NIRSpec PRISM epochs (4-pixel bins, 0.8–5.0 𝜇m), offset vertically by 200 ppm per epoch for clarity and colour-coded by date, with the inverse-variance-weighted mean spectrum (black, plotted at its true depth). Grey bands mark the stellar H2O features near 1.4 and 1.85 𝜇m. The dotted line marks 2.0 𝜇m, the boundary of the region where the contamination is strongest (Section 3). The 2023 November 8 visit contains a flare during transit and the 2024 July 9 visit shows activity outside transit (Section 2.5). -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Detecting.png?resize=1200%2C716&ssl=1)
Posted inAstronomy & Telescopes
Detecting Atmospheres In The Presence Of Stellar Contamination: An Empirically Calibrated Framework Applied To Four JWST/NIRSpec PRISM Transits Of TRAPPIST-1c
[astro-ph.EP] Transmission spectroscopy of rocky exoplanets orbiting late M dwarfs is limited by stellar contamination rather than photon noise.
Posted inMars
Sulfate Deposits On Iani Chaos On Mars
[NASA/JPL-Caltech/UArizona] This HiRISE image shows light-toned layered deposits within Iani Chaos. Many of the same deposits occur within the depressions of Iani Chaos, as well as several nearby similar regions […]
Posted inAtmospheres, Climate, Weather
Ancient Seas Reveal Times When The Earth Rapidly Shifted Relative To Its Axis
[AAAS] Ancient sea-level changes provide new evidence that during the Jurassic and Cretaceous, Earth underwent episodes of rapid “true polar wander” (TPW).
Posted inMars
Following Ancient Rain Toward The Origins Of Life On Mars
[Tohoku University] The Mars we know today is a cold, dry world of dust and rocks. However, around 3.8-3.6 billion years ago, it may have looked very different. Geological and […]
Posted inTitan
Flow Dynamics Of Cryolava Or Impact Melt On Titan’s surface
[astro-ph.EP] Titan, a unique body in the solar system, resembles a life-size Miller-Urey experiment where pockets of liquid water might interact with abundant organic matter.
Posted inAway Teams & Field Reports
NASA Scientists Search For Clues About Mars’ Past In Scotland
[NASA] This summer, NASA scientists headed to the Scottish Highlands to follow up on last year’s announcement of potential biosignatures on Mars and prepare for future research.
Posted inAstrochemistry
Modeling The Radiolysis In H2O:HCOOH ice: Connecting Laboratory Experiments With Astronomical Measurements
[RSC Advances] We present a computational study of radiolytic chemistry and desorption dynamics in astrophysical ice composed of H2O:HCOOH (1 : 1), irradiated with Ni11+ ions at 46 MeV and […]
Posted inWater/Hycean Worlds & Oceanography
How Ocean Chemistry On Earth Helped Life Keep Breathing
[UC Riverside] Scientists have helped solve a longstanding mystery about how Earth remained habitable after oxygen first accumulated in its atmosphere more than 2 billion years ago, providing evidence that […]
Posted inEnceladus
How Enceladus’ Ocean Spray Becomes Chemically Diverse Ice Grains
[Institute of Science Tokyo] Saturn’s icy moon Enceladus hides a global ocean beneath its frozen surface. From fractures near its south pole, material from this ocean is ejected into space […]