James Webb Space Telescope observes the cloudy sub-Neptune HD 15337 c

Star system: HD 15337 | Distance from the Sun: 146 light years

Researchers using the James Webb Space Telescope have analyzed the atmosphere of the sub-Neptune planet HD 15337 c, which is about 2.5 times the size of Earth. The study revealed a 'featureless' spectrum, meaning the planet's atmosphere is likely very thick, enriched with heavy elements, or covered in high-altitude clouds and haze. 

Interestingly, the planet arrived for its transit earlier than expected, suggesting the presence of an undiscovered neighboring planet pulling on it with its gravity. These findings support the theory that planets with temperatures around 600 K, like HD 15337 c, often have the thickest atmospheric hazes, making them difficult to peer into even with our most powerful telescopes.

Scientific study

JWST COMPASS: NIRSpec/G395H Transmission Observations of the Sub-Neptune HD 15337 c (external link)