For the first time, astronomers have discovered evidence of powerful, changing winds on a gas giant located outside our solar system, but the unusual clouds affected by those winds are what makes HAT-P-7b such a unique planet, according to a new Nature Astronomy study.
As Space.com explains, HAT-P-7b is about 40% larger than Jupiter, is located more than 1,000 light years from Earth, and has an atmosphere that contains sparkling clouds believed to be made up of corundum – the very same mineral which forms gemstones like rubies and sapphires.
Those clouds can travel around the planet thanks to an equatorial jet that has dramatically variable wind speeds, which at their fastest can push tremendous quantities of these jewel clouds using strong winds, researchers from the University of Warwick have discovered.
Lead author Dr. David Armstrong and his colleagues found that these drastic wind changes can likely result in catastrophic storms on the planet – a discovery made by tracking variations in the amount of light reflected by HAT-P-7b and determining that the planet’s brightest point changes its position. It is said to be the first detection of weather on an extrasolar gas giant.
Winds change brightest spot, but planet tidally locked
“Using the NASA Kepler satellite,” Dr. Armstrong explained in a statement, “we were able to study light reflected from HAT-P-7b’s atmosphere, finding that the atmosphere was changing over time. HAT-P-7b is a tidally locked planet, with the same side always facing its star.”
“We expect clouds to form on the cold night side of the planet, but they would evaporate quickly on the hot dayside,” the Warwick astronomer continued. “These results show that strong winds circle the planet, transporting clouds from the night side to the dayside. The winds change speed dramatically, leading to huge cloud formations building up then dying away.”
HAT-P-7b completes one journey around its host star every 2.2 days, Space.com reported. The authors of the new study used observations made by the Kepler planet-hunting instrument from 2009 through 2013 to discovered the changing position of its brightest spot, demonstrating that it is possible for scientists to monitor weather on distant planets using changes in reflected light.
Because it is tidally locked , and orbits a star that is twice as large and 50% more massive than the Sun, HAT-P-7b could never be a habitable planet, the researchers said. The average dayside temperatures reach 2860 Kelvin (2586 degrees Celsius; 4688 degrees Fahrenheit), and the winds suggest that it is likely home to violent weather systems as well, they explained.
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Image credit: Mark Garlick/University of Warwick
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