Wed Jan 28, 2:20 PM ET

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.

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."

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Nature: http://www.nature.com/nature







Article: HERE

Distant planet is an orbiting hell

PARIS (AFP) – Astronomers have observed a planet some 200 light years from Earth that, for a few hours, becomes 700 degrees Celsius (1,300 degrees Fahrenheit) hotter every time its elliptical orbit brings it close to its sun.

The scientists, in a study released on Wednesday, say they have generated the most realistic images ever captured of an exoplanet, the name given to planets outside our Solar System.

They used infrared data collected from NASA's space-based Spitzer telescope to gain pictures of a strange world exposed briefly to an inferno.

One image shows a thin blue crescent on the "dark" side of the planet, opposite its star, while the scorched side glows a deep, crimson red.

Known as HD80606b, the planet is a giant ball of gas that has four times the mass of Jupiter, the biggest planet of our system.

Researchers led by Gregory Laughlin of the University of California at Santa Cruz analysed data collected in November 30 hours before, during and after HD80606b's closest approach to its star.

From the telescope's vantage point, the planet passed behind the star -- an event called a secondary eclipse -- just before reaching its maximum temperature of 1,227 C (2240 F), hotter than molten lava.

It was an unexpected stroke of luck, making it possible to measure the exact temperatures of the star and the planet separately.

"This is the first time that we've detected weather changes in real time on a planet outside our solar system," said Laughlin.

"The results are very exciting because they give us important clues to the atmospheric properties of the planet."

As the atmosphere heats up and expands, it produces fierce winds -- moving at five kilometers (three miles) per second -- that flow away from the day side toward the night side.

The planet's rotation causes the winds to curl up into large-scale storm systems that gradually peter out as temperatures cool, Laughlin said.

HD80606b swings around its sun in an elliptical orbit every 114 Earth days.

It is one of about a dozen so-called "hot Jupiter" extrasolar planets which spin on their axes in such a way that the same surface is always facing their respective stars.

The photo-like images were generated by a computer programme that calculated the colour and intensity of light coming from the glowing planet.

"These images are far more realistic than anything that's been done before for extrasolar planets," said UCSC researcher Daniel Kasen, who developed the programme.

When closest to its star, the sunlight beating down on the planet is more than 800 times stronger than at the far end of its egg-shaped orbit.

"If you could float above the clouds, you'd see its sun growing larger and larger at faster and faster rates, increasing in brightness by a factor of 1,000," Laughlin said.

HD80606b was discovered in 2001 by a Swiss planet-hunting team at the Geneva Observatory.

Some 300 exoplanets -- some of which may have conditions similar to those that gave rise to life on Earth -- have been identified since 1995, but astronomers say far more are waiting to be discovered.

Up to now, virtually everything known about the atmosphere of exoplanets has come from data collected by the Spitzer.





Article: HERE