Hottest Planet Ever Discovered, An Ultrahot Jupiter, Has Iron And Titanium In Its Atmosphere

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The name of “ultrahot Jupiter” speaks for itself. This newly discovered class of gas giants are the hottest planets ever detected. In fact, they’re hot enough to be stars and have sizzling surface temperatures exceeding 3,100 degrees Fahrenheit (1,700 degrees Celsius), notes Space.com.

The hottest of them all is a scorching place called KELT-9b, a gas giant three times more massive than Jupiter and twice as wide. Discovered last year with the help of the Kilodegree Extremely Little Telescope (KELT) at Winer Observatory in southeastern Arizona, KELT-9b has staggering surface temperatures of up to 7,800 degrees Fahrenheit (4,300 Celsius) on its day side (ultrahot Jupiters are tidally locked, with one side perpetually facing their parent star), Space.com reported at the time of its discovery.

That’s hotter than many of the dwarf stars dotting the Milky Way and just 2,200 degrees Fahrenheit (1,200 degrees Celsius) cooler than the surface of the sun, which makes KELT-9b the hottest alien world ever discovered, explains the University of Geneva (UNIGE) in Switzerland.

Although ultrahot Jupiters are too hot to be habitable, these sweltering gas giants are utterly fascinating nonetheless, shows New Atlas, particularly when it comes to their atmospheric properties.

As the Inquisitr previously reported, these planets are hot enough for water molecules to disintegrate on their day side and recombine on their night side. And, as it turns out, KELT-9b is so fiery, it even vaporized heavy metals.

According to a new study, published yesterday in the journal Nature, astronomers have found iron and titanium vapors in KELT-9b’s atmosphere.

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This incredible discovery marks the first time that these heavy metals have ever been detected in the atmosphere of an exoplanet. Everything started with a theoretical study of the air around KELT-9b, conducted by UNIGE scientists in collaboration with researchers from the University of Bern (UNIBE), also in Switzerland.

“This planet is a unique laboratory to analyze how atmospheres can evolve under intense stellar radiation,” said David Ehrenreich, principal investigator with the UNIGE team.

Curious to see what they would find in the atmosphere of the hottest known planet, the combined team ran simulations that predicted the air around KELT-9b would contain iron vapor.

“The results of these simulations show that most of the molecules found there should be in atomic form, because the bonds that hold them together are broken by collisions between particles that occur at these extremely high temperatures,” said Kevin Heng, study co-author and a UNIBE professor.

Intrigued by what they had found, the scientists analyzed the planet’s spectrum with the HARPS-North spectrograph on the Galileo National Telescope in Spain and uncovered the fingerprint of iron vapor really does exist in KELT-9b’s atmosphere.

But that’s not all they found, notes UNIGE. In addition to iron, HARPS-North also picked up the signature of titanium vapor — a first in exoplanet discoveries.

“With the theoretical predictions in hand, it was like following a treasure map,” explained study lead author Jens Hoeijmakers, affiliated with both UNIGE and UNIBE. “And when we dug deeper into the data, we found even more.”

So, what has created the astounding conditions that make all this possible? Well, first of all, the gas giant orbits a blistering star almost twice as hot as the sun. Dubbed KELT-9, this flaming star lies 650 light-years from Earth in the Cygnus constellation (the Swan) and has a surface temperature of more than 18,032 degrees Fahrenheit (10,000 degrees Celsius).

Secondly, the planet circles its star in a very tight orbit and sits 30 times closer to KELT-9 than Earth to the sun. This proximity makes KELT-9b complete a full orbit in just 36 hours and become heated to extreme temperatures.

“The nearby warm blue star covers 35 degrees in the planet’s sky, about 70 times the apparent size of the sun in the Earth’s sky. Under this scorching sun, the planet’s atmosphere is warm enough to shine in reddish-orange tones and vaporize heavy metals such as iron and titanium,” reveals UNIGE in a news release.