Hellishly Hot Planet Hits Highs of 2,240 Degrees Fahrenheit

WASHINGTON – Astronomers have found a planet with a galactic case of hot flashes.

In just six hours, this planet four times the size of Jupiter heats up by more than 1,200 degrees, according to a study published in Thursday's issue of the journal Nature.

"It's the first observation of changing weather" on a planet outside our solar system, said study author Gregory Laughlin, an astronomy professor at the University of California at Santa Cruz.

He used NASA's Spitzer Space Telescope to study the planet.

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Change is a mild way to put it for the lifeless world, called HD80606b, where the word "mild" would never enter a weather forecast.

Normally, the planet is a toasty 980 degrees or so. But in the few hours it whips around its sun the planet gets zapped with mega-heat, pushing the thermometer closer to 2,240 degrees.

During its brief close pass to its sun, the planet is 10 times nearer its star than Mercury is to our sun.

When it comes closest to its star, it becomes one giant "brewing storm" complete with shock waves, Laughlin said. The radiation bombarding the planet is 800 times stronger than when it is farthest away.

Then just as quickly, the planet slingshots away and radiates the heat to the cool vacuum of space. It glows cherry red and the temperature plummets, Laughlin said.

"Utterly bizarre," he said. "It is thoroughly completely uninhabitable. In a galaxy of uninhabitable planets, this one stands out as being completely inhospitable to life."

The planet circles its star — the larger of two stars in a binary system — in a comet-like orbit in just 111 days.

The star is visible from Earth near the Big Dipper.

On Feb. 14, HD80606b will travel between the Earth and its star. There's a 15 percent chance that amateur astronomers using small telescopes could see it swing by, obscuring a tiny part of the star, Laughlin said.

"This is indeed an oddball planet, where the temperature range of the season changes from hellish to super-hellish," said Carnegie Institution astronomer Alan Boss. "This place makes Venus look like a nice place to live, and that is saying something."