Sodium atmosphereIn 2001, sodium was detected in the atmosphere of an extrasolar planet by the Hubble Space Telescope. The planetary atmosphere of HD 209458b was the first outside our solar system to be measured. The planet, informally known as Osiris, was the first transiting planet discovered (5 Nov 1999). It orbits the sun-like star designated HD 209458. Later measurements with the Hubble Space Telescope Imaging Spectrograph (2003-4), found an enormous ellipsoidal envelope of hydrogen, carbon and oxygen around the planet with a temperature that reaches 10,000°C, resulting in a significant "tail" of atoms moving at speeds greater than the escape velocity.«[Image: artist's visualization of the planet crossing in front of its sun-like star.] |
