When Impacts Bring Back the Air: How Collisions Could Revive Atmospheres on M-Dwarf Worlds
Prune C. August and colleagues show that rocky planets orbiting M-dwarf stars may repeatedly lose and regain their atmospheres. When gases like CO₂ freeze on the nightside, meteorite impacts can re-vaporize them, temporarily restoring an atmosphere. Their models predict that such planets could spend up to 80% of their lifetimes with these transient atmospheres, reshaping how astronomers interpret atmospheric “non-detections.”
Peering Into TRAPPIST-1e: JWST’s First Glimpses of a Habitable-Zone Rocky World
Espinoza and collaborators used JWST to observe four transits of TRAPPIST-1 e, a rocky planet in the habitable zone. They found that stellar activity strongly contaminates the data but developed new statistical methods to handle it. Their results rule out a thick hydrogen-rich atmosphere, suggesting TRAPPIST-1 e, if it has an atmosphere, likely hosts heavier gases such as carbon dioxide.
TRAPPIST-1 d: Searching for Signs of Air on a Nearby Earth-Sized World
Astronomers used JWST to study TRAPPIST-1 d, an Earth-sized planet near the habitable zone of its star. The data revealed a flat transmission spectrum, ruling out thick atmospheres of hydrogen, methane, water vapor, or carbon dioxide. This suggests TRAPPIST-1 d is either airless, has only a very thin atmosphere, or is shrouded by high-altitude clouds, offering key insights into how rocky planets around small stars evolve.
Building Earth Through Cosmic Collisions: How Giant Impacts Shaped Rocky Planets
The study by Maeda and Sasaki shows that Earth-like planets form through repeated giant impacts and chemical reactions between atmospheres, magma oceans, and cores. Early impacts load protoplanets with too much hydrogen, while later collisions, after the gas disk fades, strip and rebalance this excess. This sequence produces planets with core compositions and densities similar to Earth’s, highlighting the importance of timing in planet formation.
A Thick Blanket for Early Mars: Evidence of a Massive Primordial Atmosphere
Sarah Joiret and colleagues show that Mars once had a massive primordial atmosphere, captured from the solar nebula. By modeling comet impacts and comparing expected xenon delivery with today’s measurements, they find Mars’s atmosphere must have been at least 2.9–14.5 bar. This thick hydrogen-rich blanket may have warmed early Mars and shaped its volatile history.
Mapping Jupiter’s Skies: A Full-Atmosphere Model
Antonín Knížek and colleagues built the first full-atmosphere model of Jupiter, combining deep thermochemistry with upper-atmosphere photochemistry. The model predicts a mixed ammonia–ammonium hydrosulfide cloud layer, stable nitrogen levels from quenching, and a stratospheric region where hydrogen cyanide forms at detectable levels. These results bridge gaps between earlier models and make new, testable predictions for future missions.
A Breath of CO₂: Searching for Life-Friendly Planets through Atmospheric Clues
This study explores how future space missions like LIFE could detect trends in atmospheric CO₂ across many exoplanets to identify signs of habitability or life. Using simulations and statistical modeling, the authors show that CO₂ patterns influenced by geology—and potentially biology—can be detected in planet populations, though observational biases must be addressed for reliable results.
Hunting for Hidden Signs of Life: How Earth-like Biosignatures Challenge Astronomers
Amber Young and colleagues explored whether signs of life—specifically, chemical disequilibrium like Earth's O₂-CH₄ mix—can be detected on exoplanets. Using simulated observations and thermodynamics modeling, they found that such biosignatures are difficult to detect around Sun-like stars and only marginally easier around M dwarfs under extremely low-noise conditions. Their work outlines critical challenges and paths forward for future life-detection missions.
A Silicate Sky: Revisiting the Atmosphere of WASP-39 b with JWST
Ma et al. use a hybrid modeling approach to reinterpret JWST data from WASP-39 b, suggesting silicon monoxide (SiO) and silicate clouds explain key spectral features, previously attributed to sulfur dioxide. Their model fits observations well, highlighting the role of silicon-based chemistry and offering a new strategy for studying exoplanet atmospheres.