Astronomers Unveil 3D Structure of an Alien Planet's Atmosphere

For the first time, astronomers have mapped the 3D structure of an alien planet's atmosphere, revealing new insights into its climate and atmospheric composition. This breakthrough helps scientists better understand exoplanet weather patterns and atmospheric dynamics, bringing us closer to uncovering the mysteries of distant worlds beyond our solar system.

WASP-121b is classified as an "ultra-hot Jupiter," a type of large gas giant that orbits very close to its star, resulting in extreme temperatures. Its atmosphere, similar to Jupiter’s, consists primarily of hydrogen and helium. However, the atmosphere of WASP-121b is unlike any other observed so far.

For the first time, astronomers have successfully mapped the three-dimensional structure of an exoplanet's atmosphere. This research revealed three distinct layers, resembling a wedding cake, on a gas planet that orbits a star hotter and larger than our Sun.

Using all four units of the European Southern Observatory’s Very Large Telescope in Chile, researchers were able to observe WASP-121b’s atmosphere, also known as Tylos. They discovered that the planet’s atmosphere has layers with varying chemical compositions and intense winds.

Previously, scientists have identified the chemical makeup of exoplanet atmospheres, but they were unable to map the vertical structure or distribution of these elements.

WASP-121b, an ultra-hot Jupiter, has a similar atmosphere to Jupiter, but its composition and behavior are unique due to its extreme proximity to its host star. The atmosphere’s base layer contains iron, which is in a gaseous form due to the planet’s intense heat. Strong winds transport gas from the planet's hot side to its cooler side.

The middle layer contains sodium and is characterized by winds circulating around the planet at 43,500 miles (70,000 kilometers) per hour, faster than any winds in our solar system. The upper layer, rich in hydrogen, loses some of its material to space.

Julia Victoria Seidel, the lead astronomer on the study, noted that this atmospheric structure is unprecedented and challenges existing theories about how atmospheres should behave.

Titanium was also detected in the gaseous atmosphere of WASP-121b. Unlike Earth, where metals like iron and titanium remain solid due to lower temperatures, WASP-121b's high temperatures allow these metals to remain in the gas phase. Earth's upper atmosphere does, however, contain sodium.

Bibiana Prinoth, a co-author of the study, emphasized that this research pushes the limits of current telescopes and instruments.

WASP-121b has a mass similar to Jupiter’s but is twice its diameter, making it a larger and puffier planet. Located about 900 light-years away in the constellation Puppis, the planet orbits its star in just 1.3 Earth days, at a distance of about 2.5% that of Earth’s distance from the Sun.

This tidally locked planet has one side constantly facing its star, with temperatures on the star-facing side reaching 4,900°F (2,700°C), and the opposite side at around 2,200°F (1,250°C). Its host star, WASP-121, is about 1.5 times the size and mass of our Sun and is hotter as well.

Understanding the structure of exoplanet atmospheres is crucial as astronomers search for planets with conditions that may support life.

As Prinoth suggests, in the future, similar observations may be made for smaller and cooler planets that resemble Earth. The European Southern Observatory's Extremely Large Telescope, set to be completed by the end of the decade, will play a key role in these advancements.

Seidel added that these studies are essential for understanding our place in the universe and whether Earth’s climate is unique. The study reveals the immense diversity of climates across exoplanets, suggesting that our home planet may not be as exceptional as once thought.

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Source: NDTV‍