Scientists find 'gemstones' in atmosphere of bizarre, scorching-hot 'marshmallow' exoplanet

Astronomers using the James Webb Space Telescope have mapped the complex atmosphere of WASP-17b, an exoplanet located roughly 1,300 light-years from Earth. The planet measures about twice the width of Jupiter despite holding only 0.8 times its mass, giving the distant world a puffy consistency. Researchers applied a new analytical approach called transmission strings to track starlight passing through the planet's outer edge as it crossed in front of its host star.

This method allowed scientists to move beyond traditional flat-circle models and map the atmosphere in three dimensions. The data revealed that WASP-17b features a structured ring shape with prominent localized anomalies that scientists compared to gemstones. The planetary analysis showed that high temperatures and chemical compositions shift dramatically between the dayside and nightside.

One prominent atmospheric feature forms where hot winds reach the equator and the cooler nightside expands. Because the planet sits extremely close to its parent star, it remains tidally locked with one permanent day side and one night side. Published on October 14 in Nature Astronomy, the findings provide a working proof of concept that distant planets can be studied as dynamic three-dimensional objects.

Researchers stated that the results align closely with existing theoretical models