Astronomers have, for the first time, unveiled the three-dimensional structure of the atmosphere of a planet outside our solar system, resembling a layered wedding cake on a blazingly hot gas giant orbiting a star bigger and hotter than our sun.
Using all four telescope units of the European Southern Observatory's Very Large Telescope in Chile, the research team observed WASP-121b, also known as Tylos. This "ultra-hot Jupiter" boasts a unique composition with stratified layers composed of varying chemical elements, and powerful winds sweeping across its atmosphere.
The researchers identified three distinct layers by detecting specific elements: iron in the lower layer due to the extreme heat, sodium in the middle layer, where intense circular winds blow, and hydrogen in the upper layer, with some escaping into space. Titanium was also detected in gaseous form, contrasting with Earth where such metals remain solid due to lower temperatures.
Astronomer Julia Victoria Seidel noted the unprecedented nature of this atmospheric structure, challenging existing predictions and demonstrating the diverse climates present in the universe. The study, led by Seidel and published in a journal this week, sheds light on the possibilities for discovering atmospheres of smaller, potentially habitable exoplanets in the future.
Beyond its scientific significance, understanding exoplanet atmospheres provides crucial context for Earth's own uniqueness in the cosmic landscape. As research progresses, the range of planetary climates discovered underscores the vast diversity awaiting exploration.