For the first time, researchers have watched weather conditions shift on a planet outside our solar system, and say the temperature spikes are out of this world. Normally, the planet is a toasty 980 degrees [Fahrenheit] 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…. When it comes closest to its star, it becomes one giant “brewing storm” [AP].
The gas giant, known as HD 80606b, lies about 190 light-years away in the constellation Ursa Major, and has an extremely elliptical orbit. When it’s closest to its sun, it is barely more than 300,000 miles away – not much more distant than our cold moon is from us. But when the planet is farthest away from its sun and coolest, it’s nearly 70 million miles away. That would be like some object flying somewhere far out between the orbits of Earth and Venus [San Francisco Chronicle]. One complete orbit around its sun takes 111 days.
Researchers say the exoplanet may top the list of the least hospitable places known to man, and say it’s impossible that any life as we know it could survive there. “This is indeed an oddball planet, where the temperature range of the season changes from hellish to super-hellish,” said … astronomer Alan Boss. “This place makes Venus look like a nice place to live and that is saying something” [AP].
For the study, published in Nature [subscription required], the astronomers used the Spitzer Space Telescope to observe the exoplanet for a 30-hour period. Lead researcher Gregory Laughlin and his team lucked out by discovering that the planet passes behind its star in an eclipse just before the moment of its closest approach. The eclipse allowed the astronomers to separate the planet’s heat from the star’s heat, and measure precisely how hot the planet gets as it cozies up to its star. By feeding the temperature measurements into a computer simulation, the researchers were able to model the planet’s weather and reveal that global storms and shockwaves erupt on HD 80606b as it dives in near to its star [Wired News].
What the researchers have seen of HD 80606b’s orbit indicates that there’s a 15 percent chance that the planet will pass in front of its sun (as seen from Earth) on February 14th. That would provide fascinating new information about the overheated world. During a transit, the planet blocks some of its host star’s light, allowing astronomers to take a more direct measurement of the object’s size. In addition, some of the starlight gets filtered through the planet’s atmosphere. Astronomers can then read signals in the light that indicate the types of gases present [National Geographic News].
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Image: NASA/JPL-Caltech/J. Langton