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Supersonic winds hurtle around exoplanet

The winds move at 2 kilometers per second. That’s about 7 times faster than the speed of sound and 20 times faster than any winds ever recorded on Earth.

This illustration shows the planet HD 189733b is shown here in front of its parent star. A belt of wind around the equator of the planet travels at 5400mph from the heated day side to the night side. The day side of the planet appears blue due to scattering of light from silicate haze in the atmosphere. The night side of the planet glows a deep red due to its high temperature.

This illustration shows the planet HD 189733b is shown here in front of its parent star. A belt of wind around the equator of the planet travels at 5400mph from the heated day side to the night side. The day side of the planet appears blue due to scattering of light from silicate haze in the atmosphere. The night side of the planet glows a deep red due to its high temperature. Image credit: Mark A. Garlick/University of Warwick

Researchers have discovered a belt of winds hurtling around an exoplanet at over two kilometers per second – that’s about 5,400 miles per hour. The University of Warwick researchers say that the winds are 20 times faster than anything ever recorded on Earth

The wind was found on a planet 63 light years from Earth named HD 189733b. The discovery is the first time that a weather system on a planet outside of Earth’s solar system has been directly measured and mapped.

The research was published in Astrophysical Journal Letters in November, 2015. Tom Louden, of the University of Warwick’s Astrophysics group is the lead researcher. Louden said:

Whilst we have previously known of wind on exoplanets, we have never before been able to directly measure and map a weather system.

HD 189733b is one of the most studied of a class of planets known as ‘Hot Jupiters‘. At over 10% larger than Jupiter, but 180 times closer to its star, HD 189733b has a temperature of 1200’C. Its size and relatively closeness to our solar system make it a popular target for astronomers. Past research has shown that the day side of the planet would appear a bright shade of blue to the human eye, probably due to clouds of silicate particles high in its atmosphere.

The researchers measured the velocities on the two sides of HD 189733b and found a strong wind moving at over 5400mph blowing from its dayside to its night side. The data was collected by HARPS, the High Accuracy Radial velocity Planet Searcher, in La Silla, Chile.

The researchers say that the techniques used could help the study of Earth-like planets. Co-researcher, Dr Peter Wheatley of the University of Warwick’s Astrophysics Group said:

We are tremendously excited to have found a way to map weather systems on distant planets. As we develop the technique further we will be able to study wind flows in increasing detail and make weather maps of smaller planets. Ultimately this technique will allow us to image the weather systems on Earth-like planets.

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Bottom line: Research published in Astrophysical Journal Letters in November, 2015 describes a belt of winds hurtling around the equator of exoplanet HD 189733b at over 2 kilometers per second. The discovery is the first time that a weather system on a planet outside of Earth’s solar system has been directly measured and mapped.

Read more from the University of Warwick

Eleanor Imster

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