Skip to main content

Wild exoplanet has metal clouds and rain of liquid gems

In the pantheon of weird exoplanets, one of the strangest has to be WASP-121 b. It’s so close to its star that not only is its surface temperature estimated to be up to an unimaginable 4,600 degrees Fahrenheit, but gravitational forces are pulling the planet apart and shaping it like a football. Now, new research reveals what the weather might be like on this hellish planet, and it’s just as weird as you might think.

Located 855 light-years away, the planet is a type called a hot Jupiter because it’s comparable in mass to Jupiter, at 1.2 times its mass, but its diameter is nearly twice as large. One reason that the planet has such extreme conditions is that it’s close to its star that it is tidally locked, meaning one side of the planet called the dayside always faces the star and has the hottest temperature, while the cooler side called the nightside always faces away from the star into space.

Artist's impression of the exoplanet WASP-121 b.
Artist’s impression of the exoplanet WASP-121 b. It belongs to the class of hot Jupiters. Due to its proximity to the central star, the planet’s rotation is tidally locked to its orbit around it. As a result, one of WASP-121 b’s hemispheres always faces the star, heating it to temperatures of up to 3000 degrees Celsius. The night side is always oriented towards cold space, which is why it is 1500 degrees Celsius cooler there. Patricia Klein and MPIA

In this new study, researchers from the Max Planck Institute for Astronomy looked at the water cycle between the planet’s dayside and nightside. It’s always too hot there for water to form clouds, but that doesn’t mean there aren’t cloudy skies there. The researchers found the nightside has some wild weather phenomena including metal clouds. The clouds consist of metals like iron, magnesium, chromium, and vanadium, which melt into their gas form on the dayside and condense into liquid clouds on the nightside.

And it gets weirder still. The researchers didn’t find indications of aluminum or titanium in the atmosphere, which they expected. They think these metals must have condensed and fallen as rain in lower levels of the atmosphere which they couldn’t see.

“This rain would be unlike any known in the Solar System,” the Max Planck Institute for Astronomy writes. “For instance, aluminum condenses with oxygen to form the compound corundum. With impurities of chromium, iron, titanium, or vanadium, we know it as ruby or sapphire. Liquid gems could therefore be raining on the nightside hemisphere of WASP-121 b.”

Researchers want to study this planet in more detail to learn about its strange ways, and they plan to observe it further using the recently launched James Webb Space Telescope.

“It’s exciting to study planets like WASP-121 b that are very different to those in our Solar System because they allow us to see how atmospheres behave under extreme conditions,” co-author Joanna Barstow said in a statement.

The research is published in the journal Nature Astronomy.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
James Webb investigates a super puffy exoplanet where it rains sand
Artistic concept of the exoplanet WASP-107b and its parent star. Even though the rather cool host star emits a relatively small fraction of high-energy photons, they can reach deep into the planet’s fluffy atmosphere.

Exoplanets come in many forms, from dense, rocky planets like Earth and Mars to gas giants like Jupiter and Saturn. But some planets discovered outside our solar system are even less dense than gas giants and are a type known informally as super-puff or cotton candy planets. One of the least dense exoplanets known, WASP-107b, was recently investigated using the James Webb Space Telescope (JWST) and the planet's weather seems to be as strange as its puffiness.

The planet is more atmosphere than core, with a fluffy atmosphere in which Webb spotted water vapor and sulfur dioxide. Strangest of all, Webb also saw silicate sand clouds, suggesting that it would rain sand between the upper and lower layers of the atmosphere. The planet is almost as big as Jupiter but has a tiny mass similar to that of Neptune.

Read more
Hubble spots an Earth-sized exoplanet just 22 light-years away
An artist’s concept of the nearby exoplanet, LTT 1445Ac, which is the size of Earth. The planet orbits a red dwarf star.

Although astronomers have now discovered more than 5,000 exoplanets, or planets outside of the solar system, the large majority of these planets are considerably larger than Earth. That's partly because it's easier to spot larger planets from tremendous distances across space. So it's exciting when an Earth-sized planet is discovered -- and the Hubble Space Telescope has recently confirmed that a nearby planet, which is diminutive by exoplanet standards, is 1.07 times the size of Earth.

The planet LTT 1445Ac was first discovered by NASA's Transiting Exoplanet Survey Satellite (TESS) in 2022, but it was hard to determine its exact size due to the plane of its orbit around its star as seen from Earth. “There was a chance that this system has an unlucky geometry and if that’s the case, we wouldn’t measure the right size. But with Hubble’s capabilities we nailed its diameter,” said lead researcher Emily Pass of the Harvard-Smithsonian Center for Astrophysics in a statement.

Read more
James Webb sees evidence of an ocean-covered ‘Hycean’ exoplanet
This illustration shows what exoplanet K2-18 b could look like based on science data. K2-18 b, an exoplanet 8.6 times as massive as Earth, orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light years from Earth.

The James Webb Space Telescope has once again peered into the atmosphere of an exoplanet, and this time it has identified indications that the planet could be covered in oceans. The planet K2-18 b is just 120 light-years away from Earth in the constellation of Leo and is a type of planet called a sub-Neptune which is unlike any planet in our solar system.

Researchers used Webb to investigate K2-18 b, which is more than eight times the mass of Earth and orbits a small, cool dwarf star. It is located within the habitable zone of the star, where it is possible for water to exist on the planet's surface, and the data suggests that this could be an ocean world.

Read more