Telescope detects cloud formation on planet 690 light years from Earth

Astronomers were able to observe a continuous cycle of cloud formation and disappearance on a planet located about 690 light-years from Earth. The phenomenon was identified on the exoplanet WASP-94 A b with data obtained by the James Webb Space Telescope (JWST) and disclosed in a study published this week by the journal Nature.

The discovery made it possible to reconstruct meteorological patterns on the planet without observing it directly. Instead, the researchers looked at small changes in the light emitted by the host star, WASP-94 A, as the planet passed in front of it.

According to the study, thick clouds continually form on the night side of the planet, a region permanently facing away from the star. As atmospheric winds carry these clouds toward the sunlit side, they quickly dissipate due to the extreme temperatures.

The work was led by researchers who used James Webb to analyze subtle differences in the spectrum of starlight during different moments of the planet's transit. The data showed that the part of the atmosphere that appears first in front of the star has intense cloud cover, while the region that appears later appears practically without cover.

Scientists estimate that these clouds are not composed of water, but of droplets of minerals. This is because the temperature on the daytime side of the planet exceeds 1,600 kelvin, a condition incompatible with the existence of liquid water.

According to the authors, ignoring these differences between the day and night sides could lead to misinterpretations about the chemical composition of the atmosphere. Instead of identifying clouds forming on the dark side, the data could suggest the presence of a permanent fog on the light side, a scenario that would indicate a different atmospheric origin.

Atmospheric analysis of exoplanets is considered one of the main tools for understanding how these worlds form and evolve. The WASP-94 system also attracts additional interest from researchers because it is part of a double star system, in which WASP-94 B orbits the same region of space.

With information from Nature*

Source: CNN