'Ruby' clouds blown across exoplanet

The weather of a gas giant exoplanet has been observed for the first time, and astronomers have found a stormy atmosphere pushing 'ruby' and 'sapphire' clouds across its atmosphere.

Published: December 14, 2016 at 12:00 pm

An artist’s impression of gas giant exoplanet HAT-P-7b, which astronomers have been studying to learn more about its weather patterns. Credit: University of Warwick/Mark Garlick


Astronomers have been able to detect weather patterns, stormy winds and ‘ruby’ and ‘sapphire’ clouds on a gas giant exoplanet 1,400 lightyears away.

The discovery marks the first time weather systems have been observed on a gas giant outside our Solar System.

HAT-P-7b is 16 times larger than Earth and orbits a star twice as large as the Sun.

Astronomers used the Kepler space telescope to observe light reflecting off the the exoplanet’s atmosphere, showing that its brightest point shifts position.

This shift is caused by an equatorial jet with strong wind speeds that pushes clouds across the planet, revealing its weather to be stormy and dramatically changing.

The study also found that clouds on the HAT-P-7b would likely consist of corundum, the mineral that forms rubies and sapphires.

"Using the NASA Kepler satellite we were able to study light reflected from HAT-P-7b’s atmosphere, finding that the atmosphere was changing over time,” says Dr David Armstrong of the University of Warwick, who led the research. “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.

“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.


This is the first detection of weather on a gas giant planet outside the Solar System.”

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