22 March 2023

James Webb Space Telescope spots scorching swirling clouds on remote planet

22 March 2023

Swirling hot sand clouds have been detected on a distant planet by Nasa’s James Webb Space Telescope.

Researchers pinpointed silicate cloud features in the distant planet’s atmosphere.

They found that the atmosphere is constantly rising, mixing and moving during its 22-hour day, bringing hotter material up and pushing colder material down.

Researchers say the resulting brightness changes are so dramatic that it is the most variable planetary-mass object known to date.

No other telescope has identified so many features at once for a single target

The team, led by Brittany Miles of the University of Arizona, also made clear detections of water, methane and carbon monoxide with data from the telescope, and found evidence of carbon dioxide.

This is the largest number of molecules ever identified all at once on a planet outside our solar system.

Cataloged as VHS 1256 b, the planet is about 40 light years away from Earth and orbits not one, but two stars over a 10,000-year period.

Dr Miles said: “VHS 1256 b is about four times farther from its stars than Pluto is from our sun, which makes it a great target for Webb.

“That means the planet’s light is not mixed with light from its stars.”

According to the researchers, higher up in its atmosphere, where the silicate clouds are churning, temperatures reach a scorching 1,500 degrees Fahrenheit (830 degrees Celsius).

The telescope detected both larger and smaller silicate dust grains within these clouds.

Co-author Beth Biller, of the University of Edinburgh, said: “The finer silicate grains in its atmosphere may be more like tiny particles in smoke.

“The larger grains might be more like very hot, very small sand particles.”

The researchers found that the planet has low gravity compared to more massive brown dwarfs, which means its silicate clouds can appear and remain higher in its atmosphere where Webb can detect them.

Another reason its skies are so turbulent is the planet’s age.

Only 150 million years have passed since it formed – making it quite young in astronomical terms – and it will continue to change and cool over billions of years.

In many ways, the team considers the findings to be the first “coins” pulled out of a spectrum that researchers view as a treasure chest of data.

Dr Miles said: “We’ve identified silicates, but better understanding which grain sizes and shapes match specific types of clouds is going to take a lot of additional work.

“This is not the final word on this planet – it is the beginning of a large-scale modelling effort to fit Webb’s complex data.”

While all of the features the researchers observed have been spotted on other planets, other research teams typically identified only one at a time.

“No other telescope has identified so many features at once for a single target,” said co-author Andrew Skemer, of the University of California, Santa Cruz.

He added: “We’re seeing a lot of molecules in a single spectrum from Webb that detail the planet’s dynamic cloud and weather systems.”

The findings are published in The Astrophysical Journal Letters.

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