A team of astronomers using NASA’s Spitzer Space Telescope has mapped temperature variations over the surface of the giant gas planet HD 189733b, revealing it is likely being whipped by roaring winds.
“We have mapped the temperature variations with longitude across the entire surface of the planet that is so far away its light takes 60 years to reach us,” said Heather Knutson of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
Mild Temperature, Furious Winds
The planet has a warm spot 30 degrees east of “high noon,” or the point directly below its star, implying that fierce winds are blowing eastward if it is tidally locked to its parent star.
Since the planet’s overall temperature variation is mild, scientists believe winds must be spreading the heat from its permanently sunlit side around to its dark side.
Such winds might be raging across its surface at up to 6,000 mph.
The findings appear in the May 9 issue of the journal Nature.
Scorching in the Shade
“Hot Jupiters” are sizzling, giant gas planets that zip closely around their stars. Roughly 50 of the more than 200 known planets outside our solar system, called “exoplanets,” are hot Jupiters.
HD 189733b, located in the constellation Vulpecula, is the closest known transiting planet, which means that it crosses in front and behind its star when viewed from Earth. It races around its star every 2.2 days.
Spitzer measured the infrared light coming from the planet as it circled around its star, revealing its different faces.
These infrared measurements, comprising about a quarter of a million data points, were then assembled into pole-to-pole strips and ultimately used to map the temperature of the entire surface of the cloudy, giant planet.
The observations reveal that temperatures on this balmy world are fairly even, ranging from 1,200 F on the dark side to 1,700 F on the sunlit side.