For the first time, scientists have created a three-dimensional map of a distant planet’s atmosphere. Using data from the James Webb Space Telescope (JWST) and a method called eclipse mapping, researchers studied the exoplanet WASP-18b, a gas giant about 400 light-years away. The findings were published recently in the journal Nature Astronomy. This technique could lead to mapping other planets in the universe, providing more insights into their atmospheres.
“Eclipse mapping helps us visualize exoplanets we can’t see clearly because their stars shine too brightly,” said Ryan Challener, a researcher at Cornell University. He noted that this method could help us understand distant planets in ways similar to how we study those in our own solar system.
WASP-18b is quite massive—about ten times the size of Jupiter—and it completes its orbit around its star in just 23 hours. Being tidally locked means one side always faces the star while the other side remains dark, creating unique temperature zones.
As WASP-18b moves behind its star, the changing light allows scientists to measure temperature variations in the atmosphere. Eclipse mapping captures these changes, making it possible to pinpoint temperature and altitude across the planet’s atmosphere.
In their study, scientists built upon a previous two-dimensional map of WASP-18b by utilizing different wavelengths of light. For instance, they used wavelengths absorbed by water to analyze the upper atmosphere. Light that passed through to lower altitudes helped them view various layers of the atmosphere in more detail.
The researchers discovered two distinct temperature regions. The area facing the star, known as the “hotspot,” is significantly warmer, surrounded by a colder ring. This temperature difference suggests that winds may not distribute heat evenly across the planet. Interestingly, the hotspot has less water than the average across the planet, indicating the extreme temperatures could be breaking down water molecules.
“We think that’s evidence of the intense heat in this region,” Challener explained, adding that this finding supports earlier theoretical predictions. It’s exciting for scientists to confirm these theories through direct observation.
What’s next? More observations with JWST could enhance the resolution of WASP-18b’s atmospheric map. The technique developed here can also be applied to study other gas giants. “This approach will allow us to learn more about exoplanets in 3D, which is incredibly exciting,” Challener stated.
In recent discussions on social media, many users expressed awe and curiosity about the implications of mapping distant planets. The excitement reflects a growing interest in space exploration and our understanding of the universe.
As this research progresses, it may change our view of planetary atmospheres, helping to answer fundamental questions about their compositions and behaviors. The future of exploring and understanding these distant worlds is promising.
