Astronomers Unveil First 3D Map of an Exoplanet’s Atmosphere
Scientists have mapped the first-ever three-dimensional structure of an exoplanet’s atmosphere, uncovering unexpected chemical layers and extreme winds.
Scientists Unravel the Atmospheric Layers of an Extreme Exoplanet
For the first time in history, astronomers have successfully mapped the three-dimensional structure of an exoplanet’s atmosphere, unveiling distinct chemical layers similar to a stratified cake. This groundbreaking discovery sheds new light on planetary atmospheres beyond our solar system, particularly in extreme environments.
The subject of this historic study, WASP-121b—also called Tylos—is an “ultra-hot Jupiter,” a gas giant orbiting perilously close to its host star. Scientists harnessed the combined power of all four telescope units of the European Southern Observatory’s (ESO) Very Large Telescope in Chile, revealing an intricate layering of atmospheric components and unexpectedly fierce jet streams.
A New Frontier in Atmospheric Exploration
Until now, astronomers could only determine the chemical makeup of exoplanet atmospheres without understanding how these elements were distributed vertically. The findings on WASP-121b change that. Researchers identified three distinct atmospheric layers, each dominated by different chemical signatures.
The lowest layer teems with iron in gaseous form, evidence of the extreme heat ravaging the planet. Winds transport these gases from the scorching, permanently lit side of the planet to its relatively cooler dark side. The middle layer features a prominent presence of sodium, where jet streams rage at an astonishing speed of 43,500 miles per hour (70,000 km/h)—far surpassing any wind system recorded in our solar system. The uppermost layer, dominated by hydrogen, is slowly escaping into space due to the planet’s searing temperatures.
“This structure has never been observed before and defies current predictions as to how atmospheres should behave,” stated Julia Victoria Seidel, an astronomer at the ESO and the Observatoire de la Côte d’Azur in France, and lead author of the study published in Nature.
A Planet Unlike Anything Seen Before
WASP-121b challenges existing theories of planetary atmospheres. Its composition primarily consists of hydrogen and helium, much like Jupiter, yet its extreme conditions set it apart from any known planet. The research team also detected gaseous titanium, an element that, along with iron, is found as a solid metal on Earth due to our cooler climate. Interestingly, Earth shares one trait with WASP-121b—an atmospheric sodium layer—though under vastly different conditions.
“For me, the most exciting part of this study is that it operates at the very limits of what is possible with current telescopes and instruments,” remarked Bibiana Prinoth, co-author and doctoral student at Lund University in Sweden.
WASP-121b: A Giant in an Extreme Orbit
Located approximately 900 light-years away in the constellation Puppis, WASP-121b boasts roughly the same mass as Jupiter but is nearly twice its diameter, giving it a bloated, puffed-up appearance. The planet orbits its host star at an astonishingly close distance—just 2.5% of the distance between Earth and the Sun. This proximity means that WASP-121b completes a full orbit in only 1.3 Earth days.
The planet is tidally locked, meaning one side perpetually faces its star while the other remains in darkness, similar to how the Moon orbits Earth. The star-facing side of WASP-121b scorches at temperatures around 4,900°F (2,700°C), while the night side is still blisteringly hot at approximately 2,200°F (1,250°C).
The host star, WASP-121, is about 1.5 times the size and mass of our Sun and significantly hotter. The intense radiation from this star strips away hydrogen from the planet’s uppermost atmospheric layer, slowly leaking it into space.
What This Discovery Means for Astronomy
The ability to dissect an exoplanet’s atmospheric structure paves the way for deeper understanding of planetary climates beyond our solar system. While WASP-121b is far from habitable, this study demonstrates that planetary atmospheres behave in ways scientists never expected.
“These detailed studies are necessary to provide context for our place in the universe,” Seidel noted. “Is Earth’s climate unique? Can theories we derive from our one data point—Earth—explain the vast diversity of exoplanets?”
With the upcoming completion of the European Southern Observatory’s Extremely Large Telescope (ELT) by the decade’s end, researchers anticipate even more refined studies. The ELT, set to be the largest optical telescope in history, will enable astronomers to conduct similar analyses on smaller and cooler planets, including those that may resemble Earth.
“In the future, we will likely be able to provide similar observations for smaller and cooler planets and thus more similar to Earth,” Prinoth added. This marks a crucial step in the search for habitable worlds beyond our solar system.
Looking Ahead: The Search for Life
While WASP-121b itself is inhospitable, its complex atmospheric dynamics offer a compelling blueprint for studying exoplanets with milder conditions. By refining atmospheric models, astronomers are inching closer to identifying worlds where life could exist.
The discovery of WASP-121b’s stratified atmosphere serves as a reminder that the universe holds far more diversity than we ever imagined. Each new observation expands our understanding, reshaping planetary science and the search for Earth-like worlds.
This study marks a breakthrough in exoplanet research, proving that atmospheres beyond our solar system exhibit surprising complexity. As astronomers continue refining their techniques, the search for habitable planets takes a promising step forward. With next-generation telescopes, the dream of identifying an Earth-like world with a comprehensible climate may soon become a reality.
Source: (Reuters)
(Disclaimer: The information in this article is based on publicly available research and findings from the European Southern Observatory and related sources. Details are subject to updates as discoveries emerge. Readers should refer to official scientific publications for the most current data.)
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