33,000 km/h Winds? Scientists Just Found the Fastest Jetstream on an Alien World

A team of astronomers has uncovered the fastest planetary jetstream ever recorded, ripping across the equator of the giant exoplanet WASP-127b at an astonishing 33,000 km/h.

This discovery, made using ESO’s Very Large Telescope, reveals the extreme and complex weather of this ‘puffy’ gas world. Scientists mapped the planet’s atmospheric composition, detecting water vapor and carbon monoxide while uncovering a double-peak signal indicating powerful equatorial winds. This groundbreaking research, which sheds light on heat distribution and planetary formation, is paving the way for more detailed exoplanet weather studies with next-generation telescopes.

Supersonic Winds on WASP-127b

Astronomers have discovered incredibly fast winds tearing across the equator of WASP-127b, a giant exoplanet. These winds reach speeds of up to 33,000 km/h (21,000 mph), making them the fastest planetary jetstream ever recorded. Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile, researchers were able to track this extreme weather, offering new insights into the atmospheric dynamics of a distant world.

On Earth, storms like tornadoes, cyclones, and hurricanes can be devastating, but scientists have now identified winds on a vastly larger scale — far beyond our Solar System. Since its discovery in 2016, WASP-127b, a gas giant more than 500 light-years away, has been a subject of ongoing study. The planet is slightly larger than Jupiter but far less dense, making it exceptionally “puffy.” Now, an international team of astronomers has made a surprising find: supersonic winds are raging through its atmosphere.

The Fastest Winds Ever Measured

“Part of the atmosphere of this planet is moving towards us at a high velocity while another part is moving away from us at the same speed,” explains Lisa Nortmann, a scientist at the University of Göttingen, Germany, and lead author of the study. “This signal shows us that there is a very fast, supersonic, jet wind around the planet’s equator.”

At 9 km per second (which is close to a whopping 33,000 km/h), the jet winds move at nearly six times the speed at which the planet rotates.^[1] “This is something we haven’t seen before,” says Nortmann. It is the fastest wind ever measured in a jetstream that goes around a planet. In comparison, the fastest wind ever measured in the Solar System was found on Neptune, moving at ‘only’ 0.5 km per second (1800 km/h).

This animation shows supersonic jet winds pummeling the equator of the giant exoplanet WASP-127b, located about 520 light-years from Earth. With speeds up to 9 km per second (almost 33,000 km/h), it is the fastest jetstream of its kind ever measured in the Universe. Credit: ESO/L. Calçada

Tracking the Storms With ESO’s VLT

The team, whose research was published today in Astronomy & Astrophysics, mapped the weather and make-up of WASP-127b using the CRIRES+ instrument on ESO’s VLT. By measuring how the light of the host star travels through the planet’s upper atmosphere, they managed to trace its composition. Their results confirm the presence of water vapour and carbon monoxide molecules in the planet’s atmosphere. But when the team tracked the speed of this material in the atmosphere, they observed — much to their surprise — a double peak, indicating that one side of the atmosphere is moving towards us and the other away from us at high speed. The researchers conclude that powerful jetstream winds around the equator would explain this unexpected result.

Further building up their weather map, the team also found that the poles are cooler than the rest of the planet. There is also a slight temperature difference between the morning and evening sides of WASP-127b. “This shows that the planet has complex weather patterns just like Earth and other planets of our own System,” adds Fei Yan, a co-author of the study and a professor at the University of Science and Technology of China.

Artist’s impression of the giant exoplanet WASP-127b orbiting its host star, and the supersonic jet winds that were discovered on the planet. With speeds up to 9 km per second (almost 33 000 km/h), the wind on the planet’s equator is the fastest jetstream of its kind ever measured in the Universe. Credit: ESO/L. Calçada

A New Era in Exoplanet Research

The field of exoplanet research is rapidly advancing. Up until a few years ago, astronomers could measure only the mass and the radius of planets outside the Solar System. Today, telescopes like ESO’s VLT already allow scientists to map the weather on these distant worlds and analyze their atmospheres. “Understanding the dynamics of these exoplanets helps us explore mechanisms such as heat redistribution and chemical processes, improving our understanding of planet formation and potentially shedding light on the origins of our own Solar System,” says David Cont from the Ludwig Maximilian University of Munich, Germany, and a co-author of the paper.

The spectrum of WASP-127b shows a double peak, meaning that part of the atmosphere is moving toward us while the other part is moving away from us. In other words: there is wind circling around the planet. The larger the wavelength separation between the peaks in the spectrum, the faster the wind, which in the case of WASP-127b moves at an impressive 9 km per second. Credit: ESO/L. Calçada

The Future of Weather Forecasting on Alien Worlds

Interestingly, at present, studies like this can only be done by ground-based observatories, as the instruments currently on space telescopes do not have the necessary velocity precision. ESO’s Extremely Large Telescope — which is under construction close to the VLT in Chile — and its ANDES instrument will allow researchers to delve even deeper into the weather patterns on far-away planets. “This means that we can likely resolve even finer details of the wind patterns and expand this research to smaller, rocky planets,” Nortmann concludes.

Notes

1. While the team hasn’t measured the rotation speed of the planet directly, they expect WASP-127b to be tidally locked, meaning the planet takes as long to rotate around its own axis as it does to orbit the star. Knowing how big the planet is and how long it takes to orbit its star, they can infer how fast it’s rotating.

Reference: “CRIRES+ transmission spectroscopy of WASP-127 b – Detection of the resolved signatures of a supersonic equatorial jet and cool poles in a hot planet” by L. Nortmann, F. Lesjak, F. Yan, D. Cont, S. Czesla, A. Lavail, A. D. Rains, E. Nagel, L. Boldt-Christmas, A. Hatzes, A. Reiners, N. Piskunov, O. Kochukhov, U. Heiter, D. Shulyak, M. Rengel and U. Seemann, 21 January 2025, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202450438

The team is composed of L. Nortmann (Institut für Astrophysik und Geophysik, Georg-August-Universität, Göttingen, Germany [IAG]), F. Lesjak (IAG), F. Yan (Department of Astronomy, University of Science and Technology of China, Hefei, China), D. Cont (Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-Universität München, Germany; Exzellenzcluster Origins, Garching, Germany), S. Czesla (Thüringer Landessternwarte Tautenburg, Germany [TLS]), A. Lavail (Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, France), A. D. Rains (Department of Physics and Astronomy, Uppsala University, Sweden [Uppsala University]), E. Nagel (IAG), L. Boldt-Christmas (Uppsala University), A. Hatzes (TLS), A. Reiners (IAG), N. Piskunov (Uppsala University), O. Kochukhov (Uppsala University), U.Heiter (Uppsala University), D. Shulyak (Instituto de Astrofísica de Andalucía, Glorieta de la Astronomía, Spain), M. Rengel (Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany), and U. Seemann (European Southern Observatory, Garching, Germany).

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