Extreme exoplanet has metal vapor clouds and rains liquid gems

(ORDO NEWS) — The giant exoplanet, 855 light-years away, is so extreme that it has clouds of vaporized metals and pours liquid rubies and sapphires.

Astronomers came to this conclusion after studying its atmosphere – the most detailed such analysis to date, revealing for the first time the conditions and dynamics of the exoplanet’s permanent night side.

“Despite the discovery of thousands of exoplanets, we have only been able to study the atmospheres of a small fraction of them due to the complex nature of the observations,” says astronomer Thomas Mikal-Evans of the Max Planck Institute for Astronomy in Germany.

“Now we’re moving beyond isolated images of individual regions of exoplanet atmospheres and studying them as the 3D systems they really are,” he adds.

The exoplanet in question is one of the most famous and well-studied to date. It is called WASP-121 b and was first discovered in 2015. It is a gas giant with a mass 1.18 times larger and 1.81 times larger than Jupiter, in a close orbit of its star for only 1.27 days. Two years after its discovery, WASP-121 b became the first exoplanet to have water detected in its stratosphere.

However, it is extremely unlikely that WASP-121 b would be habitable. In such a close orbit, it is very hot, its temperature fluctuating between 1500 and 3000 Kelvin (1227-2727 degrees Celsius, or 2240-4940 degrees Fahrenheit).

The size and proximity of WASP-121 b to its host star WASP-121 place it in the category of hot Jupiters – gas giant exoplanets whose orbits with host stars are less than 10 days. Of the nearly 5,000 exoplanets confirmed to date, more than 300 fall into this extreme category, but WASP-121 b has been called the “prototype” of superhot Jupiters.

Because WASP-121 b is in such a close orbit, it also sticks to its star, which happens when the orbiting body rotates at the same speed as it does.

This means that the exoplanet always faces one side of its star, where there is constantly scorching daylight, and the other side is always turned to the side, where it is constantly dark. Previous studies of the atmosphere of WASP 121 b found heavy metal vapors in the atmosphere of its dayside.

The night side is a bit more difficult to explore as it is about 10 times darker than the day side. To get more detailed information about the entire exoplanet, Mikal-Evans and his team used the Hubble Space Telescope to observe two complete orbits of WASP-121 b, combining data from the day and night side to see the global functioning of the atmosphere.

This detailed, shifting spectrum of light allowed them to observe and reconstruct the full water cycle of an exoplanet for the first time.

“We saw this water feature and displayed how it changed in different parts of the planet’s orbit,” explains Mikal-Evans. “This encodes information about how the temperature of the planet’s atmosphere varies with altitude.”

Here on Earth, the water cycle includes phase transitions as water changes into vapor, liquid, and solid (ice). On the WASP-121 b, even on the night side, the temperature is too high for the solid or liquid phase of the water.

Instead, on the dayside, where temperatures exceed 3,000 Kelvin, the loss of energy from water molecules causes them to glow in the infrared. Under the influence of temperature, they can even collapse, decomposing into hydrogen and oxygen.

The night side is much cooler, though still insanely hot by Earth standards, with temperatures dropping to 1,500 Kelvin. This extreme temperature difference between the hemispheres creates a constant difference in pressure, which creates extreme westerly winds that sweep around the exoplanet, carrying water molecules and atoms with them.

“These winds are much faster than our jet stream and can likely move clouds around the planet in about 20 hours,” says astrophysicist Tansu Deilan of the Massachusetts Institute of Technology.

When these winds reach the night side of WASP-121 b, the temperature becomes low enough to return the water to a vapor state, after which it is transferred back to the day side.”

But the water will not condense into clouds. Instead, the team’s research indicates that nightside temperatures are cold enough that clouds could form from the metals previously detected in WASP-121 b’s atmosphere. Among them are vanadium, iron, chromium, calcium, sodium, magnesium and nickel, but, interestingly, neither aluminum nor titanium.

The team thinks these elements may have condensed and settled deeper into WASP 181 b’s atmosphere where we can’t detect them. There, aluminum can combine with oxygen to form the mineral corundum, a crystalline form of aluminum oxide. Here on Earth, when mixed with trace amounts of other metals such as vanadium, iron, chromium or titanium, it forms rubies and sapphires.

This means the WASP-181 b can rain gems. Although Neptune and Uranus can also rain gems – we have no hope of collecting them anyway – WASP-181 b shows us what an amazing variety can exist in different types of worlds.

The team has already booked time on the recently launched James Webb Space Telescope to make additional observations of WASP-181 b. They hope to find carbon monoxide to learn more about how hot Jupiters form.

We believe that they cannot be born near their stars; According to our current models of planetary formation, gravity, radiation, and intense stellar winds keep the gas from sticking together. Webb’s observations may help solve this mystery.

“This will be the first time we will be able to measure the carbon molecules in this planet’s atmosphere,” Mikal-Evans says. “The amount of carbon and oxygen in the atmosphere gives an idea of ​​where these planets form.”

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