Hurricanes in space? See how Hubble revealed extreme weather on a distant planet

Stormy weather on display for 'hot Jupiter'

the JupiterThe WASP-121 b-sized planet is not a place to call home. For starters, it orbits near a star brighter and hotter than the Sun. The planet is so dangerously close to its star that its upper atmosphere is a blazing 3,400 degrees F – Hotter than a steel furnace.

A torrent of ultraviolet radiation from the host star heats the planet's upper atmosphere, causing magnesium and iron gas to escape into space. Strong gravitational tidal forces from the star have changed the shape of the planet so that it appears more like the shape of a football. By combining several years of Hubble Space Telescope Through observations using computer modeling, astronomers have found evidence of massive hurricanes swirling over the infernal planet. Tornadoes are frequently created and destroyed by the large temperature difference between the star-facing side and the dark, night side of the planet. Exoplanet.

This is an artist's concept of the exoplanet WASP-121 b, also known as Tylos. The exoplanet's appearance is based on data from Hubble's simulation of the object. Using Hubble observations, another team of scientists had previously reported the discovery of heavy metals such as magnesium and iron escaping from Jupiter's extremely hot exoplanet's upper atmosphere; Marking it as the first such discovery. The exoplanet orbits dangerously close to its host star, approximately 2.6% of the distance between Earth and the Sun, putting it on the verge of being torn apart by the star's tidal forces. Strong gravitational forces have changed the shape of the planet. Image credits: NASA, ESA, Quentin Changat (ESA/STScI), Mehdi Zamani (ESA/Hubble)

The Hubble Space Telescope observes the change in the atmosphere of an exoplanet over a period of 3 years

By combining several years of observations from NASAUsing the Hubble Space Telescope, along with computer modeling, astronomers have found evidence of massive hurricanes and other dynamic weather activity swirling on a hot Jupiter-sized planet, 880 light-years away.

The planet, called WASP-121 b, is uninhabitable. But this result represents an important early step in studying weather patterns on distant worlds, and perhaps eventually finding habitable exoplanets with stable, long-lasting climates.

Over the past few decades, detailed telescopic and spacecraft observations of neighboring planets in our solar system have shown that their turbulent atmospheres are not static but constantly changing, just like the weather on Earth. This discrepancy should also apply to planets orbiting other stars as well. But it takes a lot of detailed monitoring and computational modeling to actually measure such changes.

A breakthrough in observing extrasolar weather

To make this discovery, an international team of astronomers compiled and reprocessed Hubble observations of WASP-121 b taken in 2016, 2018 and 2019.

They found that the planet has a dynamic atmosphere that changes over time. The team used sophisticated modeling techniques to prove that these dramatic time differences can be explained by weather patterns in the exoplanet's atmosphere.

This visualization shows temperature forecasts over 130 exoplanet days, across sunrise, noon, sunset and midnight, for the exoplanet WASP-121 b, also known as Tylos. The brighter yellow areas depict areas on the exoplanet's dayside where temperatures rise above 2,100 degrees Kelvin (3,320 degrees Fahrenheit); Because of its proximity to its host star, about 2.6% of the distance between Earth and the Sun. Because of the extreme temperature difference between the day and night sides, astronomers suspect that evaporated iron and other heavy metals that seep into the upper layers of the atmosphere on the day side partly fall back into the lower layers, making it rain iron at night. Some heavy metals also escape the planet's gravity from the upper atmosphere. Image credits: NASA, ESA, Quentin Changat (ESA/STScI), Mehdi Zamani (ESA/Hubble)

The team found that the atmosphere of WASP-121 b shows noticeable differences between observations. Even more interesting is that there can be huge weather fronts, huge storms and hurricanes that are repeatedly created and destroyed due to the large temperature difference between the side facing the star and the dark side of the exoplanet. They also detected a clear offset between the hottest region of the exoplanet and the point closest to the star on the planet, as well as a variation in the chemical composition of the exoplanet's atmosphere (as measured by spectroscopy).

The team reached these conclusions using computational models to help explain observed changes in the exoplanet's atmosphere. “The exquisite detail of exoplanetary atmosphere simulations allows us to accurately model the weather on very hot planets like WASP-121 b,” explained Jack Skinner, a postdoctoral fellow at the California Institute of Technology in Pasadena, California, and co-leader. From this study. “Here we take an important step forward by combining observational constraints with atmospheric simulations to understand time-varying weather on these planets.”

“This is a very exciting result as we move forward in observing weather patterns on exoplanets,” said Quentin Changat, one of the team's principal investigators. European Space Agency A research fellow at the Space Telescope Science Institute in Baltimore, Maryland. “Studying exoplanetary weather is vital to understanding the complexity of exoplanetary atmospheres on other worlds, especially in the search for exoplanets with habitable conditions.”

This visualization shows weather patterns on the exoplanet WASP-121 b, also known as Tylos. This video has been slowed down to observe patterns in the exoplanet's atmosphere in more detail. Image credits: NASA, ESA, Quentin Changat (ESA/STScI), Mehdi Zamani (ESA/Hubble)

WASP-121 b: A case study in extrasolar atmospheres

WASP-121 b is so close to its parent star that its orbital period is only 1.27 days. This proximity means that the planet is tidally locked so that one hemisphere always faces the star, in the same way that our Moon always has the same side pointing toward Earth. Daytime temperatures approach 3,450°F (2,150°K) on the star-facing side of the planet.

The team used four sets of archival Hubble observations of WASP-121 b. The full data set included observations of WASP-121 b passing in front of its star (taken in June 2016); WASP-121 b passes behind its star, also known as the secondary eclipse (captured November 2016); and the brightness of WASP-121 b as a function of its phase angle relative to the star (the varying amount of light received on Earth from an exoplanet as it orbits its parent star, similar to the Moon's phase cycle). These data were taken in March 2018 and February 2019, respectively.

“The combined data set represents a significant amount of observation time for a single planet, and is currently the only consistent set of these repeated observations,” Changat said. The information we extracted from those observations was used to infer the chemistry, temperature, and cloudiness present in WASP-121 b's atmosphere at different times. This has provided us with a fascinating picture of how the planet has changed over time.

Hubble's unique capabilities are also evident in the wide range of science programs it will enable through observations of Cycle 31, which began on December 1. About two-thirds of Hubble's time will be devoted to imaging studies, while the rest will be devoted to spectroscopic studies. , such as those used on WASP-121 b. More details about Course 31 Science are in A Last ad.

Reference: “Is the atmosphere of very hot Jupiter WASP-121b variable?” By Quentin Changat, Jack W. Skinner, James Y.K. Zhu, Jonas Natella, Ingo B. Waldmann, Ahmed F. Al-Rifai, Akren Derrick, Billy Edwards, Thomas Mikal Evans, Max Joshua, Giuseppe Murillo, Nour Skaf, Angelos Tsiaras, Olivia Vinot and Kai Ho Yip, January 2, 2023, Astrophysics > Earth and planetary physics Astrophysics.
arXiv:2401.01465

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, operates the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts science operations on Hubble and Webb. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, DC