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.