Solar Flare Burns Away Atmosphere of Exo-Planet

Interesting (unless it should happen to us). From the Daily Mail:

A few hours before Hubble observed the planet for the second time, Swift recorded a powerful flash of radiation coming from the surface of the star, in which the star briefly became 4 times brighter in X-rays.

Co-author Peter Wheatley, from the University of Warwick, said: 'X-ray emissions are a small part of the star's total output, but it is the part that it is energetic enough to drive the evaporation of the atmosphere.

'This was the brightest X-ray flare from HD 189733A of several observed to date, and it seems very likely that the impact of this flare on the planet drove the evaporation seen a few hours later with Hubble.'

X-rays are energetic enough to heat the gas in the upper atmosphere to tens of thousands of degrees, hot enough to escape the gravitational pull of the giant planet.

A similar process occurs, albeit less dramatically, when a space weather event such as a solar flare hits the Earth's ionosphere, disrupting communications.