James Webb records dust storm on exoplanet – 03/23/2023 – Science

A violent dust storm has been observed on a planet outside our Solar System for the first time.

The phenomenon was detected on the exoplanet known as VHS 1256b, which is about 40 light years from Earth.

The remarkable capabilities of the new James Webb Space Telescope (JWST) were needed to make the discovery.

The dust particles detected are formed by silicates —small grains composed of silicon and oxygen, which form the basis of most rocky minerals.

But the storm detected by Webb isn’t exactly the same phenomenon you’d find in an arid, desert region of our planet. She is more of a rocky mist.

“It’s like taking grains of sand, but much finer. We’re talking about grains of silicate the size of smoke particles,” explains Beth Biller, a professor at the University of Edinburgh and the Royal Observatory Edinburgh, UK.

“This is how the clouds in VHS 1256b would become much, much hotter. This planet is a hot, young object. The temperature at the top of the cloud is perhaps similar to that of a candle flame”, estimates the expert.

VHS 1256b was first identified by the Vista telescope, developed in the UK and operating in Chile since 2015.

That planet is what’s called a “super Jupiter”—similar to the gas giant in our own Solar System, but much larger, perhaps 12 to 18 times the mass of the “original” Jupiter.

It circles some stars at a great distance — about four times Pluto’s distance from the Sun.

Earlier observations of VHS 1256b showed it to have a red appearance, suggesting it might have dust in its atmosphere. The study based on Webb’s analyzes confirms just that.

“This is fascinating, because it illustrates how clouds on another planet can be different from the clouds of water vapor we are familiar with on Earth,” says Biller.

“We see carbon monoxide (CO) and methane in the atmosphere, which indicates that the cloud [do VHS 1256b] it’s hot and turbulent, with material drawn from the depths.”

“Probably there are several layers of silicate grains. The ones we see are made up of very fine grains, which are higher up in the atmosphere. But there may be larger grains in lower layers”, adds the researcher.

Other telescopes have already detected silicates in so-called brown dwarfs. These objects are essentially similar to stars that failed to ignite properly.

But this is the first time the phenomenon has been seen in an object the size of a planet.

To make the detection, Webb used the Mid-Infrared Instrument (Miri) and Near-Infrared Spectrometer (NirSpec) tools.

They didn’t take pretty pictures of the planet — at least not in this case. What the instruments did was separate the light coming from VHS 1256b into its component colors, as a way of discerning the composition of the atmosphere.

“The JWST is the only telescope that can measure all of these molecular and dust features together,” says Professor Gillian Wright, one of the project’s co-investigators and director of the STFC UK Center for Technology in Astronomy, also in Edinburgh.

“The dynamic image of the atmosphere of VHS 1256b provided by this study is an excellent example of the discoveries made possible by using the advanced features of Miri and NirSpec together”, completes the expert.

JWST’s main mission is to observe the pioneering stars and galaxies that first shone just a few hundred million years after the Big Bang.

But another purpose of the telescope is to investigate exoplanets. On Miri and NirSpec, he has the tools to study the atmospheres of these objects in unprecedented detail.

From this technology, some scientists hope to even be able to say whether some exoplanets have suitable conditions to host life.

Astronomers reported Webb’s observations of VHS 1256b in The Astrophysical Journal Letters.

James Webb is a collaborative project of space agencies in the United States, Europe and Canada. It was launched in December 2021 and is considered the successor to the Hubble Space Telescope.