[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 […]
sub-Neptune
![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.
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 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.
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Lava / magma ocean / Volcanic Worlds, Neptune, Status Report, Uranus, Water/Hycean Worlds & Oceanography
Ice Giants Revisited: Uranus And Neptune As Magma Ocean Worlds
Uranus and Neptune are commonly interpreted as volatile-rich “ice giants”, an assumption that underpins most interior models.
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography
COUNTESS I: A Uniformly Vetted Catalog of Known and New Transiting Exoplanets in the TESS Northern Continuous Viewing Zone
The Transiting Exoplanet Survey Satellite (TESS) has transformed the study of nearby exoplanetary systems; however, its nominal observing strategy limits sensitivity to planets with orbital periods shorter than ∼10 days […]
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Stellar Cartography
Finding Patterns in Planets: Researchers Explore the Demographics of Alien Worlds in K2 Data
Our galaxy is jam-packed with planets, with thousands already discovered and millions more expected to eventually come into view. Within this ever-growing bounty, surprises have abounded, revealing that our solar […]
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Ice Giant, Imaging & Spectroscopy, Status Report
Escape Of Water- And Metal-enriched Atmospheres From Compact Hot mini-Neptunes With CHAIN
Recent observations reveal that atmospheric compositions of close-in sub-Neptunes are diverse and can differ strongly from pure H/He-dominated.
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Impact of Clouds on the Atmosphere-Mantle Interface of Sub-Neptunes
Sub-Neptunes are among the most common type of close-in planets found in our galaxy, yet their bulk composition remains largely uncertain; H-rich envelopes overlaying rocky cores, volatile-rich planets, and carbon-rich […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Press Release
A New Global Chemical Equilibrium Code: Refractory Element Signatures in Super-Earths and Sub-Neptunes
The atmospheres of super-Earths and sub-Neptunes can be strongly modified by chemical exchange with their molten interiors during long-lived magma ocean phases. Interpreting atmospheric observations requires fast models that self-consistently […]