Patchy clouds on Jupiter-like alien planet found

Cosmic clouds! For the first time, astronomers have mapped clouds around a planet beyond our solar system - a giant sizzling, Jupiter-like world.
The planet, known as Kepler-7b, is marked by high clouds in the west and clear skies in the east, astronomers, using data from NASA's Kepler and Spitzer space telescopes, found.
Previous studies from Spitzer have resulted in temperature maps of planets orbiting other stars, but this is the first look at cloud structures on a distant world.
"By observing this planet with Spitzer and Kepler for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet," said lead author of the study Brice-Olivier Demory of Massachusetts Institute of Technology in Cambridge.

"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," said Demory.
Kepler has discovered more than 150 exoplanets, which are planets outside our solar system, and Kepler-7b was one of the first.

Kepler's visible-light observations of Kepler-7b's moon-like phases led to a rough map of the planet that showed a bright spot on its western hemisphere.
But these data were not enough on their own to decipher whether the bright spot was coming from clouds or heat. The Spitzer Space Telescope played a crucial role in answering this question.

Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it between 815 and 982 degrees Celsius.
This is relatively cool for a planet that orbits so close to its star - within 0.6 astronomical units - and, according to astronomers, too cool to be the source of light Kepler observed.
Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west 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," said Thomas Barclay, Kepler scientist at NASA's Ames Research Center in Moffett Field, California.

"Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time - it has a remarkably stable climate," said Barclay.
The findings are an early step toward using similar techniques to study the atmospheres of planets more like Earth in composition and size.
The study appears in the Astrophysical Journal Letters.