This artist's concept shows a Jupiter-like planet soaking up the scorching rays of its nearby "sun." Image credit: NASA/JPL-Caltech
Posted on 10/13/2006 11:45:54 AM PDT by SunkenCiv
The researchers used Spitzer to determine the temperature variation in the atmosphere of a nearby planet called Upsilon Andromedae b. This "hot-Jupiter" planet is a gas giant similar to Jupiter, but it orbits very close to its scorching star, circling the star once every 4.6 days.
Scientists believe the planet is tidally locked to its star. This means it is rotating slowly enough that the same side always faces the star, just as the same side of Earth's tidally locked moon always faces toward us, hiding its "dark side." However, since this planet is made of gas, its outer atmosphere could be circulating much faster than its interior.
According to the astronomers, the observed temperature difference between the two sides of Upsilon Andromedae b is extreme -- about 1,400 degrees Celsius (2,550 degrees Fahrenheit). Such a large temperature difference indicates the planet's atmosphere absorbs and reradiates sunlight so fast that gas circling around it cools off quickly. This is unlike Jupiter, which is even-temperatured all the way around.
(Excerpt) Read more at nasa.gov ...
This artist's concept shows a Jupiter-like planet soaking up the scorching rays of its nearby "sun." Image credit: NASA/JPL-Caltech
Spitzer observed Upsilon Andromedae b at five points during the planet's trip around its star. The planet's light levels went up or down, as detected by Spitzer, depending on whether the planet's sunlit or dark side was pointed toward Earth. These data indicate that the temperature difference between the two hemispheres of the planet is about 1,400 degrees Celsius (2,550 degrees Fahrenheit). [*]The surface of our Sun is about 5800 degrees Kelvin (what we old-timers sometimes still refer to as degrees centrigrade, except as calculated from Absolute Zero, instead of the freezing point of water; Online Conversion shows me 5800 kelvin = 9980.33 degree Fahrenheit).
Ironic, since he (Zeus) was such a hot-tempered sort...
Since Jupiter only has one eye (the Great Red Spot; the Little Red Spot doesn't count,yet), maybe it's really Cyclops. ;')
You know, given the temperatures indicated this "gas giant" might have a solid core (pure speculation). The reason could be simple, it'd need a strong gravity well deep down to prevent the upper atmosphere from expanding and boiling off as it passes through the day side. Also, I'd suspect that thermal expansion would give the planet an irregular shape anyway ... or at least stir up / even out the atmosphere as cooling gasses "fall" back to lower altitudes.Great observations. Our own gas giants are believed to have solid cores of some size or other.
Nifty!
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