For the first time, astronomers have found a planet outside our solar system that has a weather system complete with strong winds and changing cloud cover. The exoplanet HAT-P-7b is located about 1,000 light-years away in the Cygnus constellation. The Jupiter-like giant gas planet is about 16 times larger than Earth.
HAT-P-7b was discovered in 2008
Astronomers led by David Armstrong of the University of Warwick analyzed four years of data from the planet HAT-P-7b taken by Kepler telescope. The planet was discovered by Kepler in 2008, but it was nondescript until now. David Armstrong said changes in the amount of light reflected by the planet’s atmosphere suggested that its brightest point kept shifting position on a timescale of tens or hundreds of days.
The planet’s repeatedly shifting bright spot was due to changes in the atmosphere as strong winds pushed clouds around. HAT-P-7b is tidally locked to its host star, which means one side of the planet always faces the star. Armstrong said clouds form on the cold night side of the planet. They are transported to the dayside by strong winds, where clouds would evaporate quickly due to extremely high temperatures.
The planet is unlikely to be habitable
The temperature on the dayside of the planet could be as high as 2,586 degrees Celsius. “The winds change speed dramatically, leading to huge cloud formations building up then dying away,” said Armstrong. With its ridiculously high temperatures and violent weather systems, the planet is unlikely to be habitable.
Also, the clouds on HAT-P-7b are not your usual clouds. Scientists believe that the clouds are made from corundrum, a rock-forming mineral that is the raw material for gemstones like sapphires and rubies. The mineral comes in a wide range of colors including blue and red. Light reflected from the planet’s atmosphere showed signs of turbulence, said scientists.
Future telescopes could detect weather patterns on exoplanets
Though many previous studies have looked at atmospheric conditions of exoplanets, they did not analyze how the conditions continued over time in a weather system. Dr. Simon O’Toole of the Australian Astronomical Observatory said the future telescopes could be used to detect weather on distant planets, including those in the Goldilocks zone – the habitable zone around a star where liquid water could exist on a planet.
NASA’s Kepler space telescope looks for changes in the amount of light coming from target stars to detect exoplanets passing by or transiting relative to its line of sight.
Findings of the study were published in the journal Nature Astronomy.