Tue October 1, 2013
What's The Forecast On Kepler-7B? Hot And Cloudy
Originally published on Tue October 1, 2013 10:34 am
Scientists are reasonably sure that it's a cloudy day on Kepler-7b, a planet that orbits its star about 1,000 light-years away from us.
Using NASA's orbiting space telescopes, researchers publishing in Astrophysical Journal Letters say that for the first time they've been able to make a rudimentary map of the atmosphere of an extrasolar planet.
The team used faint visible light and infrared reflections from Kepler-7b to make their cloud map.
"By observing this planet with Spitzer and Kepler [telescopes] for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet," study co-author Brice-Olivier Demory of the Massachusetts Institute of Technology in Cambridge said in a statement.
"We wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signature that we interpreted as clouds," he said.
Kepler-7b is what astronomers refer to as a "hot Jupiter" — a gas giant similar to our own solar system's largest planet but that orbits much closer to its parent star. In the case of Kepler-7b, there's the additional oddity that it has far less mass than Jupiter even though it's substantially larger.
The Science World Report says the team detected an anomaly on Kepler-7b that caused them to take a closer look:
"Kepler's probe detected the presence of a bright spot on the planet's western hemisphere. But due to insufficient data, the astronomers couldn't interpret whether the bright spot was due to internal heat or it was being emitted from the clouds. To decode this mystery, the astronomers used the Spitzer Space telescope to gather hidden clues of the planet's atmosphere.
"Spitzer's ability to detect the infrared light enabled it to measure Kepler-7b's temperature ranging from 1,500-1,800 degree Fahrenheit. For a planet that orbits its star from such a close distance, this temperature is comparatively cooler. The temperature is too cool to host the light observed in Kepler's western hemisphere. Considering this fact, the astronomers believe that the light from the planet's star might be coming from the clouds on the western side of the planet."
"Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere," Thomas Barclay with NASA's Ames Research Center in Moffett Field, Calif., who works on the Kepler telescope team, said in a statement.
"Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time — it has a remarkably stable climate," Barclay said.