James Webb Space Telescope probes the mysterious atmosphere of radius-valley planet TOI-260 b

Star system: TOI-260 | Distance from the Sun: 65.9 light years

Using the James Webb Space Telescope, astronomers have examined the atmosphere of TOI-260 b, a planet roughly 1.7 times the size of Earth that sits in the mysterious 'radius valley'—a gap where few planets are found. The observations revealed a mostly flat spectrum, suggesting the planet might have a very heavy atmosphere enriched with elements other than hydrogen and helium, or perhaps hidden by high-altitude clouds.

While a small potential signal was detected at a specific wavelength, researchers believe it may be a technical artifact rather than a chemical discovery. These findings highlight the extreme diversity of small planets located between the sizes of Earth and Neptune and suggest that much more observation time is needed to solve the puzzle of their composition.

Scientific study

JWST COMPASS: A NIRSpec G395H Transmission Spectrum of Radius Valley-Dweller TOI-260 b (external link)