Treasure Chest Of Data: James Webb Space Telescope Spots Dusty Clouds On Planet Orbiting Two Stars

The planet has a 22-hour day, and its atmosphere is constantly rising, mixing and moving. The clouds have silicate dust and sand particles. 

The planet, called VHS 1256 b, is about 40 light years away from Earth, and orbits two stars over a 10,000-year period. The temperatures higher up in the planet's atmosphere are extremely high. At the upper regions of the atmosphere, the silicate clouds are churning.

Source : NASA

NASA's James Webb Space Telescope (JWST) has achieved yet another milestone by identifying the highest number of molecules ever all at once on an exoplanet. JWST, the world's most powerful space telescope, has observed dusty clouds in the atmosphere of an exoplanet that orbits two stars. 

NASA has described the findings of Webb as a "treasure chest of data".

All about the exoplanet where Webb has spotted dusty clouds

The planet has a 22-hour day, and its atmosphere is constantly rising, mixing and moving. The clouds have silicate dust and sand particles. 

Since the clouds keep rising, mixing and moving, the resulting brightness changes are extremely dramatic, making the exoplanet the most variable planetary-mass object known to date. 

The study describing the findings will be published in the The Astrophysical Journal Letters. A team of researchers, led by Brittany Miles of the University of Arizona, made extraordinarily clear detections of water, methane and carbon monoxide using the data provided by JWST, also called Webb.

The study also found evidence of carbon dioxide on the planet, called VHS 1256 b. 

VHS 1256 b is about 40 light years away from Earth, and orbits two stars over a 10,000-year period. 

In a NASA statement, Miles said VHS 1256 b is about four times farther from its stars than Pluto is from our Sun, making the exoplanet a great Target for Webb, because the planet's light is not mixed with light from its stars. 

The temperatures higher up in the planet's atmosphere are extremely high. At the upper regions of the atmosphere, the silicate clouds are churning, and the temperatures reach 830 degrees Celsius. 

Webb detected both larger and smaller silicate dust grains within those clouds. NASA has shown those dust grains on a spectrum. 

Beth Biller of the University of Edinburgh in Scotland, one of the co-authors on the paper, said the finer silicate grains in the planet's atmosphere may be more like tiny particles in smoke, and the larger particles might be more like very hot, very small sand particles.

Why are the planet’s skies turbulent?

Compared to more massive brown dwarfs, VHS 1256 b has low gravity. This means that its silicate clouds can appear and remain higher in its atmosphere where Webb can detect them. In astronomical terms, the planet is quite young, and due to its age, the skies are turbulent. Since only 150 million years have passed since the planet formed, it will continue to change and cool over billions of years. 

Miles said the researchers have identified silicates, but better understanding which grain sizes and shapes match specific types of clouds is going to take a lot of additional work. 

What makes Webb’s discovery special?

The study is special because the researchers identified the features on the planet all at once, but previous studies identified only one feature at a time, on planets elsewhere in the Milky Way. Andrew Skemer of the University of California, Santa Cruz, said no other telescope has identified so many features at once for a single target, and that the researchers are seeing a lot of molecules in a single spectrum from Webb that detail the planet's dynamic cloud and weather systems. 

What does the spectrum indicate?

The spectrum represents the amount and wavelength of light emitted by different molecules such as water, carbon monoxide, methane, and silicates. 

The researchers analysed data gathered by two instruments aboard Webb: the Near Infrared Spectrograph (NIRSpec) and the Mid-Infrared Instrument (MIRI). The researchers were able to directly observe the planet, without using a transit technique or a coronagraph, because the planet orbits at a great distance from its star.

A transit technique is a method of observing an exoplanet when it directly passes between its star and the observer, because this is when the planet dims most of the star's light, making it easier to calculate its orbit, size and other characteristics. A coronagraph is a device which blocks the light of a planet's star so that other surrounding objects can be observed clearly. 

 

The researchers analysed data gathered by two instruments aboard Webb: the Near Infrared Spectrograph (NIRSpec) and the Mid-Infrared Instrument (MIRI). The researchers were able to directly observe the planet, without using a transit technique or a coronagraph, because the planet orbits at a great distance from its star. (Photo: NASA)

The two Webb instruments observed a vast section of near- to mid-infrared light emitted by VHS 1256 b. The researchers plotted the light on the spectrum, and identified signatures of silicate clouds, water, methane and carbon monoxide. 

Since the planet is so far from its stars, it will become colder over time, and its skies may transition from cloudy to clear.