The exoplanet sub-Neptune population currently poses a conundrum. Are small-size planets volatile-rich cores without atmosphere, or are they rocky cores surrounded by H-He envelope? To test the different hypotheses from […]
sub-Neptune
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report
Probing Cold-to-Temperate Exoplanetary Atmospheres: The Role of Water Condensation on Surface Identification with JWST
Understanding the surface temperature and interior structure of cold-to-temperate sub-Neptunes is critical for assessing their habitability, yet direct observations are challenging.
Posted inAstrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Neptune, Status Report, Water/Hycean Worlds & Oceanography
Volatile-rich Sub-Neptunes as Hydrothermal Worlds: The Case of K2-18 b
Temperate exoplanets between the sizes of Earth and Neptune, known as “sub-Neptunes”, have emerged as intriguing targets for astrobiology. It is unknown whether these planets resemble Earth-like terrestrial worlds with […]
![Super-Earth occurrence for Kepler (black circles) and K2 (gray circles), TESS data assuming all candidates are real (teal square), and 99.7% confidence intervals to calculate the upper limits for TESS data assuming all candidates are false positives (teal triangles) as a function of metallicity. The [−0.25, −0.5] bin occurrence rates are offset horizontally for visual clarity. The best-fit power-law trend line for the Kepler and K2 data (yellow) is displayed and extrapolated to [Fe/H] = −0.75 showing the 1σ uncertainties (Zink et al. 2023). We show the combined best-fit exponential trend line for Kepler, K2, and TESS (purple; Equation (6)) including the 1σ uncertainties. Each metallicity bin is indicated by gray dashed lines. Within the [−0.75, −1] bin, there is insufficient data to further constrain the super-Earth occurrence rate as a function of metallicity (denoted by the gray hatched region). -- The Astronomical Journal](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/09/Formation-Of-Super-Earths-Proven.png?resize=1200%2C716&ssl=1)
Posted inAstrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
Formation Of Super-Earths Proven To Be Limited Near Metal-poor Stars
In a new study, astronomers report novel evidence regarding the limits of planet formation, finding that after a certain point, planets larger than Earth have difficulty forming near low-metallicity stars.
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Lava / magma ocean / Volcanic Worlds, Status Report
Role of Magma Oceans in Controlling Carbon and Oxygen of Sub-Neptune atmospheres
Most exoplanets with a few Earth radii are more inflated than bare-rock planets with the same mass, indicating a substantial volatile amount. Neither the origin of the volatiles nor the […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography
Phase Equilibria of Sub-Neptunes and Super-Earths
We investigate the consequences of non-ideal chemical interaction between silicate and overlying hydrogen-rich envelopes for rocky planets using basic tenets of phase equilibria. Based on our current understanding of the […]
Posted inExoplanets, -moons, -comets, Gas Giants, Status Report
The Effect Of Dynamical Interactions In Stellar Birth Environments On The Orbits Of Young close-in planetary systems
Stars do not form in isolation but together with other stars, and often in a clustered environment. Depending on the initial conditions in these environments, such as initial density and […]
Posted inAstronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Searching for Neutral Hydrogen Escape from the 120 Myr Old Sub-Neptune HIP94235b using HST
HIP94235 b, a 120 Myr old sub-Neptune, provides us the unique opportunity to study mass loss at a pivotal stage of the system’s evolution: the end of a 100 million […]
Posted inAtmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
Chemical Mapping Of Temperate sub-Neptune Atmospheres: Constraining the Deep-interior H2O/H2 Using the Atmospheric CO2/CH4
Understanding the planetary envelope composition of sub-Neptune-type exoplanets is challenging due to the inherent degeneracy in their interior composition scenarios. Particularly, the planetary envelope’s H2O/H2 ratio, which can also be […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report
First Comparative Exoplanetology Within a Transiting Multi-planet System: Comparing the atmospheres of V1298 Tau b and c
The V1298 Tau system (20-30Myr), is a benchmark young multi-planet system that provides the opportunity to perform comparative exoplanetology between planets orbiting the same star right after their formation.