14 DAY TRIAL // 153 light-years from Earth there is a planet very 'attached' to its star. HD 209458b orbits its star so close and so fast, that it's losing its atmosphere. The planet's surface is thought to reach 1,093 degrees Celsius and one year lasts three and a half days.
Astronomers discovered this gas-made planet and its 'running' atmosphere using the Hubble Space Telescope's Cosmic Origins Spectrograph. They also noticed that the gas tail was moving toward the Earth at a speed of approximately 35,400 kilometers an hour. Astronomer Cynthia Froning of the University of Colorado, said "this planet is getting blasted by the star and that's blowing the atmosphere off." This is the first observation of a planet's atmosphere being blasted away by its sun.
The phenomenon is caused by the star's extreme solar wind that evaporates the gas planet little by little; well, maybe a bit more, as the planet is loosing about 36,000 kilograms of mass a day. Theoretically, the planet will disappear in a trillion years says astronomers. They also add that this period of time is longer than the star's life. Nobody knows for how long this planet has been evaporating, but researchers can only assume it has been going on for several million years now.
The HD 209458b is one of the few known planets that crosses the face of its star periodically. This means that for the light from the star to get to Earth it needs to pass through the planet's atmosphere. Scientists will then be able to analyze the composition of the planet's atmosphere and the speed and direction in which gas escaping from it moves.
Study leader Jeff Linsky, from the University of Colorado, states that HD 209458b is the “first confirmation” that the evaporation of the atmosphere is actually real. The planet looks like a typical “hot Jupiter”, therefore this mass loss is likely to be observed in the future at most close-orbiting gas giants, under the form of comet Tails.