A planet with 5,63,000-km-long comet-like tail of gas has been discovered outside our Solar System. The exoplanet, named WASP-69 b, orbits its star every 3.9 days. The exoplanet experiences extreme atmospheric loss, shedding about 200,000 tons of gas per second, astrophysicists said. It is located around 160 light-years from Earth.