Hubble reveals dynamic weather activity on ultra-hot planet 880 light-years away

A team of astronomers using data from NASA's Hubble Space Telescope and computational models have found clear evidence of dynamic weather activity on WASP-121 b, also known as Tylos, an ultra-hot planet that lies about 880 light-years away from Earth.

The team examined Hubble observations of WASP-121 b from 2016, 2018, and 2019 and found that the atmosphere of this Juipter-sized planet is dynamic and undergoes changes over time, offering a glimpse into the exotic weather patterns of a distant gas giant. They then used computer modelling techniques to demonstrate that these temporal variations could be explained by weather patterns in the exoplanet's atmosphere.

Due to the large temperature difference between the star-facing side and the dark side of WASP-121 b, massive weather fronts, storms, and massive cyclones appeared to be created and destroyed repeatedly. Additionally, the researchers saw an apparent offset between the hottest region of the exoplanet and the point closest to its parent star. Variability in the chemical composition of the atmosphere, measured through spectroscopy, was also observed.

For this discovery, the team utilized four sets of Hubble archival observations of the exoplanet, including transits of WASP-121 b in front of its star (2016), passing behind its star, also known as a secondary eclipse in November 2016 and the brightness of the planet as a function of its phase angle to the star. These data were taken in March 2018 and February 2019, respectively.

"This is a hugely exciting result as we move forward for observing weather patterns on exoplanets. Studying exoplanets' weather is vital to understanding the complexity of exoplanet atmospheres on other worlds, especially in the search for exoplanets with habitable conditions," said one of the principal investigators of the team, Quentin Changeat, a European Space Agency Research Fellow at the Space Telescope Science Institute in Baltimore, Maryland.

While WASP-121 b isn't habitable, these results are an important early step in studying weather patterns on worlds beyond our solar system – maybe even finding potentially habitable ones: https://t.co/JyTCqrX2E5This visualization shows the exoplanet's weather patterns. pic.twitter.com/UNATdvs0Ni

— Hubble (@NASAHubble) January 4, 2024