Simulations show that exoplanets heated to deeper depths by their host stars exhibit markedly different weather patterns.

For many years, most astrophysical models assumed that planets beyond our solar system, called exoplanets, were heated to similar depths by their host stars (i.e. stars like the Sun around which planetary systems are formed). Analyzes of recent observations carried out by several collaborations using different telescopes, however, suggest that some exoplanets could absorb heat much deeper in their atmospheres than initially thought. Such exoplanets could present weather conditions very different from those expected by past modeling.

Researchers from the California Institute of Technology, the Flatiron Institute, and Brandeis University recently performed a series of simulations that confirmed this hypothesis. Their article, published in the Physical Examination Letterssuggests that the warm atmospheres of exoplanets heated by their host stars at deeper depths lead to different persistent weather patterns.

“We were motivated to examine this problem by a recent analysis of JWST data for the planet WASP-96b, which showed that heat from its host star could be absorbed much deeper into the atmosphere than we previously thought.” , said Jack W. Skinner. , Joonas Nättila and James YK. Cho, authors of the paper, told Phys.org. “This led us to look at previous analyzes of similar planets and discover that there are also other planets heated in this way.”

The main goal of Skinner, Nättilä and Cho’s recent work was to better understand how the depth of the atmosphere to which planets are heated affects their long-term weather patterns. This would make it possible to determine more precisely what a planet would look like when observed using current and future space telescopes. It would also advance our understanding of climate and, ultimately, the habitability of exoplanets.

“The exact location and distribution of heating on exoplanets is not well known at present, but previous studies have generally assumed a single location and distribution,” explained Skinner, Nättilä and Cho. “In reality, a more complete picture of the planet’s atmosphere is needed to accurately interpret the observations.”

As part of their study, the researchers performed hundreds of cutting-edge supercomputer simulations. Their simulations solve a set of complex, nonlinear equations that describe the evolution of compressible fluids on a rotating sphere. The same equations are used to predict the weather and climate on Earth and other planets in the solar system.

“We set up these simulations with the same parameters as two different hot Jupiters with different types of heating,” Skinner said.

“The heating is based on retrievals by the James Webb and Hubble Space Telescopes (the latter no longer in operation) of the hot Jupiter exoplanet WASP-96b. The main difference from previous simulation work is that our This work uses a very efficient algorithm. This allows our simulations to be performed at extremely high resolution (in fact, about 50 times higher resolution than is usually used for these planets) on powerful supercomputers.

The algorithm used by Skinner, Nättilä and Cho significantly improves their simulations, allowing them to capture small-scale flow structures such as eddies, fronts and waves. Collectively, these flow structures provide vital information about the weather conditions that could be observed on exoplanets, with unprecedented levels of detail and precision.

“Since heating and the small-scale structures it generates drive the flow, the type of heating determines how the flows behave on these planets,” Nättilä said. “Our simulations show that the atmospheres of hot Jupiters are very dynamic and turbulent, with powerful storms ranging from large to small sizes and intensities. The type and behavior of these storms depends on how heating and cooling are redistributed across the planets.”

This research team’s recent work provides interesting insights into weather conditions that might exist on planets outside the solar system and how those conditions might be affected by the depth at which heat from host stars is absorbed .

The simulations carried out as part of this study are among the most detailed and precise carried out to date and could inform the development of new models describing the atmospheres of hot exoplanets.

“Modeling and understanding flows on exoplanets is essential, because these flows move areas of warm (and cold) air (including chemicals and clouds) around the planet,” Cho explained. “This creates bright and dark spots that move around the planet and are potentially observable by current and future space telescope missions, such as JWST and Ariel.”

Skinner, Nättilä and Cho are excited about the results they have obtained so far, because they ultimately demonstrate that the atmospheres of exoplanets are very dynamic and variable, much like planet Earth. Furthermore, their work shows that although exoplanets may have very similar physical parameters and be located in planetary systems with similar host stars, subtle differences between them could have a profound impact on their climate, weather and other observable characteristics.

“Our work has opened up many more exciting questions about exoplanets and demonstrates that precise models are now essential to accurately interpret current observations and optimally plan future observations,” added Skinner, Nättilä and Cho.

“With NASA’s upcoming JWST and ESA’s ARIEL missions, our work shows that we are now able to begin to realistically constrain and test fundamental physics theories and sophisticated computational models, as well as to progress towards a robust determination of exoplanets likely to support life.”

© 2024 Science X Network