The roster of weird alien worlds has a new addition: a planet with a tail.
The gaseous extrasolar planet known as HD 209458b has been suspected of having a comet-like tail since 2003 but, being 153 light years away, it has been hard to prove.
Using the Hubble Space Telescope, and his team at the University of Colorado in Boulder has managed to study the mass the planet is shedding. They calculated the tail鈥檚 composition, direction and speed by studying changes in its host star鈥檚 ultraviolet spectra as the planet passes in front of it.
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HD 209458b is similar to Jupiter in size and composition. It orbits its star in just 3.5 days and its surface is roughly 1100 掳C. This intense heat is causing heavy elements like carbon and silicon to boil off, and be blown away by the solar wind.
鈥淚t鈥檚 a very similar phenomenon to what happens with a comet,鈥� Linsky explains. 鈥淓xcept it鈥檚 starting off as a gas planet as opposed to ice and the material in its outer atmosphere is being heated and lost. The wind from the star is pushing it away from the planet so we see a tail.鈥�
The gas trail is blowing away from the star at more than 35,000 kilometres per hour. The team estimates that the comet-like planet has a trillion years before the entire planet disappears.
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