New model measures global atmospheric wind speeds on the planet WASP-76 b

Star system: WASP-76 | Distance from the Sun: 637 light years

Atmospheric circulation on ultra-hot Jupiters—massive gas planets that orbit very close to their host stars—can be studied by observing how light emitted by the planet shifts in frequency. A new computational method has been developed to translate these subtle light shifts into precise measurements of wind speeds across the planet’s surface. This approach provides a clearer picture of how gases move on extreme worlds like WASP-76b.

To test this model, the team applied it to synthetic thermal emission spectra of WASP-76b. By analyzing the data, they successfully recovered the speed of the planet's equatorial jet, matching previous complex climate simulations to within 1 kilometer per second. The model focuses on four key wind characteristics, including flow speed and the direction of air currents, to build a detailed map of atmospheric movement.

This method demonstrates that using specific spectral resolutions allows for the identification of global wind patterns while minimizing errors caused by model inaccuracies. The results highlight that combining observations from both before and after the planet passes behind its star provides the most accurate data. This helps researchers better understand how heat and gas circulate in the intense environments of distant solar systems.

Key findings
- A new model effectively maps wind speeds on ultra-hot Jupiters using only four primary parameters.
- Equatorial jet speeds on WASP-76b were calculated to within 1 kilometer per second of established simulations.
- Spectral resolution of 100,000 was identified as the ideal balance for resolving global wind features.
- Observations taken before and after planetary eclipses produce more reliable wind flow measurements.

Scientific study

Parametrizing the projected wind fields of ultra-hot Jupiters in thermal emission: an application to GCM spectra of WASP-76b (external link)