24th June 2010
Looks like the wind’s picking up…
On an extrasolar planet 150 light years away in the constellation Pegasus, there are winds that would make even the most violent hurricanes on Earth look like a gentle breeze. Astronomers using ESO’s VLT (Very Large Telescope) have detected a superstorm with frightening wind speeds, of between 5,000 and 10,000 kilometeres per hour…kind of on the gusty side!
This exoplanet called HD209458b is 60% the size of Jupiter, and hugs it’s parent star much closer in than Mercury does to our Sun. This means it gets roasted to temperatures of 1,000 C on the side that permanently faces the star in it’s orbit, while the other side of the planet is in constant night and so is far cooler.
You will probably know just how temperature differences on Earth cause the winds to blow and hurricanes to form, but on this exoplanet the temperature difference is massive between the hot day side, and the cool night side of this alien world. A ferociously powerful superstorm of carbon monoxide gas is the result of this difference, that blows from the hot side to the cooler side of the planet.
Measuring winds on an exoplanet like this has never been done before so this is a first. This was achieved by using the doppler effect of the motion of the gas in the planet’s atmosphere. Astronomers also measured the mass of the planet and it’s parent star, that is quite similar to our Sun.
You might be able to lick your finger and hold it up to the breeze to get an idea of how strong it is and from what direction, but to measure just how fast the wind is blowing on some alien planet 150 light years away, well that’s pretty damn amazing…and from ground based observations too!
Astronomers may be able to use this type of study of a planets atmosphere in the search for extraterrestrial life.
