Recent detections of carbon-bearing molecules in the atmosphere of a candidate Hycean world, K2-18 b, with JWST are opening the prospects for characterising potential biospheres on temperate exoplanets.
We analyze four super-Earth exoplanets, LHS 1140 b, K2-18 b, TOI-1452 b, and TOI-1468 c, which orbit M-dwarf stars in the habitable zone.
JWST is revolutionising the study of temperate sub-Neptunes, starting with the first detection of carbon-bearing molecules in the habitable-zone sub-Neptune K2-18 b. The retrieved abundances of CH4 and CO2 and […]
Understanding the surface temperature and interior structure of cold-to-temperate sub-Neptunes is critical for assessing their habitability, yet direct observations are challenging.
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 […]
The search for habitable conditions and signs of life on exoplanets is a major frontier in modern astronomy. Detecting atmospheric signatures of Earth-like exoplanets is challenging due to their small […]
![Comparisons between the theoretical transmission spectra generated by EPACRIS (solid lines) and the JWST observations for (Top) H2:H2O=50:50 and [C+N+S]=100×solar metallicity scenario of K2-18 b assuming Ab = 0.3 corresponding to the left panel of Figure 4, and (Bottom) H2:H2O=75:25 and [C+N+S]=100×solar metallicity scenario of TOI-270 d assuming Ab = 0 corresponding to the right panel of Figure 4. The grey symbols with error bars indicate JWST observations of corresponding exoplanets taken from Madhusudhan et al. (2023) for K2-18 b (Top), and Benneke et al. (2024) for TOI-270 d (Bottom). Each color represents a spectrum generated by excluding specific species: green for no CH4, red for no CO2, light blue for no OCS, blue for no H2O, teal for no CO, light brown for no NH3, and black for all species included. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2024/06/Chemical-Mapping-of.png?resize=1200%2C720&ssl=1)
Understanding the envelope composition of sub-Neptune-type exoplanets is challenging due to the inherent degeneracy in their interior composition scenarios. Particularly, the H2O/H2 ratio, or can be expressed as the O/H […]
Exoplanets are common in our galaxy, and some even orbit in the so-called habitable zone of their star. NASA’s James Webb Space Telescope has been busy observing a few of […]
The study of temperate sub-Neptunes is the new frontier in exoplanetary science. A major development in the past year has been the first detection of carbon-bearing molecules in the atmosphere […]
Theoretical predictions and observational data indicate a class of sub-Neptune exoplanets may have water-rich interiors covered by hydrogen-dominated atmospheres. Provided suitable climate conditions, such planets could host surface liquid oceans.
