NASA telescopes find clouds in planet beyond solar system

Astronomers using data from NASA’s Kepler and Spitzer space telescopes have created the first cloud map of a planet beyond our solar system, a sizzling, Jupiter-like world known as Kepler-7b. The planet is marked by high clouds in the west and clear skies in the east, NASA said Monday. 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. Massachusetts Institute of Technology in Cambridge lead author Brice-Olivier Demory said, “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. Demory is the author of a paper accepted for publication in the Astrophysical Journal Letters. “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 added. Kepler has discovered more than 150 exoplanets, which are planets outside our solar system, and Kepler-7b was one of the first. The telescope’s problematic reaction wheels prevent it from hunting planets any more, but astronomers continue to pore over almost four years’ worth of collected data. 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. Like Kepler, Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet’s atmosphere. Spitzer’s ability to detect infrared light means it was able to measure Kepler-7b’s temperature, estimating it between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin). 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. The findings are an early step toward using similar techniques to study the atmospheres of planets more like Earth in composition and size, NASA said.