This distant marshmallow-like exoplanet has 'gemstones' in its atmosphere
What's the story
Astronomers have discovered "gemstones" in the atmosphere of a bizarre and scorching-hot exoplanet, WASP-17b. The planet, which is located some 1,300 light-years away from Earth, has a mass about 0.8 times that of Jupiter but is twice as wide. This gives it a "super-puff" consistency similar to marshmallows on Earth. It completes an orbit around its parent star in less than four Earth days due to its close proximity.
Innovative method
Mapping WASP-17b's atmosphere
The unique atmospheric composition of WASP-17b was mapped using a new technique called "transmission strings."
The method involves creating detailed 3D models of the exoplanet's atmosphere by tracking it as it transits in front of its star.
This captures the light spectrum around the planet's atmosphere from different angles, providing a more comprehensive view than traditional methods that only average light across the entire limb.
Atmospheric structure
Dayside and nightside differences
The atmospheric model created by the team shows that WASP-17b's atmosphere is ring-shaped, with distinct "gems" protruding from it.
The research also indicates that the chemical composition and temperature of this exoplanet's atmosphere vary between its dayside and nightside, which is consistent with theoretical predictions.
This difference is likely due to the planet being tidally locked, with one side always facing its star and receiving constant stellar radiation.
Technique validation
Proof of concept
The successful application of the transmission strings technique on WASP-17b is a major milestone in studying the atmospheres of other exoplanets.
The research was published in Nature Astronomy.
"This is proof of concept that planets are, in fact, 3D objects," said Lili Alderson from Cornell University. "To move beyond computational exercises and see it for real is a different matter."