NASA Webb unravels the mysteries of the silicate clouds of planet VHS 1256

Using NASA’s James Webb Space Telescope, researchers have detected silicate clouds in the atmosphere of a distant planet. The atmosphere is constantly rising, mixing and moving throughout its 22-hour day, lifting warmer materials and pushing colder down. The resulting brightness changes are so sharp that it is the most variable planetary object known today. The team, led by Brittany Miles of the University of Arizona, also used Webb’s data to detect water, methane and carbon monoxide with extraordinary clarity, and also found signs of carbon dioxide. This is the largest number of molecules identified simultaneously on a planet outside our solar system.

The planet, cataloged as VHS 1256 b, is about 40 light-years away and orbits two stars, not once every 10,000 years. “VHS 1256 b is about four times further from its star, Pluto, than our Sun, making it an excellent target for Webb,” Miles said. “This means that the light of the planet does not mix with the light of its stars.” Higher in its swirling atmosphere of silicate clouds, temperatures reach scorching 1,500 degrees Fahrenheit (830 degrees Celsius).

In these clouds, Webb found both larger and smaller particles of silicate dust shown in the spectrum. “Smaller silicate particles in its atmosphere can be like tiny particles in smoke,” said co-author Beth Biller of the University of Edinburgh in Scotland. “Larger grains can be more like very hot, very small sand particles.”

VHS 1256 b has lower gravity compared to larger brown dwarfs, meaning that silicate clouds can form and stay higher in the atmosphere where Webb can detect them. Another reason why the sky is so active is the age of the planet. He is quite young from an astronomical point of view. Only 150 million years have passed since its formation, and it will continue to change and cool for billions of years.

In many ways, the team sees these findings as the first “coins” to be taken off the spectrum, which researchers view as a wealth of data. In many ways, they are just beginning to set their content. “We have identified silicates, but a lot of additional work will be needed to better understand what grain sizes and shapes correspond to specific cloud types,” Miles said. “This isn’t the last word on this planet – it’s the beginning of large-scale modeling to match Webb’s complex data.”

While all the elements the team observed have been detected by other telescopes on other planets in the Milky Way, other research teams have typically only identified one at a time. “No other telescope has detected so many features for a single target at once,” said Andrew Schemer of the University of California, Santa Cruz. “We see many molecules in a single spectrum of Webb detailing the planet’s dynamic cloud cover and weather systems.”

As this team and others continue to look at Webb’s high-resolution infrared data, there will be more to learn about VHS 1256 b in the months and years to come. “A very modest telescope time has a huge payoff,” Biller added. “With just a few hours of observation, we have a seemingly endless potential for new discoveries.”